What should be in the NetWorks file. Hosts file. Where is the hosts file. Network file service What should be in the Networks file

Sometimes Networks errors and others system errors Windows can be associated with problems in the Windows registry. Several programs can use the Networks file, but when these programs are deleted or changed, sometimes "orphaned" (erroneous) Windows registry entries remain.

In principle, this means that while the actual path to the file could be changed, its incorrect former location is still recorded in the Windows registry. When Windows tries to find a file on this incorrect link (on the location of the files on your computer), Networks error may occur. In addition, malware infection could damage the registry entries related to Microsoft Windows.. Thus, these damaged Windows registry entries must be corrected to eliminate the problem at the root.

Editing the Windows registry manually in order to delete the Networks key errors is not recommended if you are not a PC maintenance specialist. Errors made when editing the registry can lead to the inoperability of your PC and put irreparable damage to your operating system. In fact, even one comma, delivered not in the place, can prevent the download of the computer!

Because of this risk, we strongly recommend using a trusted registry cleaner such as WinThruster (Developed by Microsoft Gold Certified Partner) to scan and repair any NetWorks-related registry problems. Using the registry cleaner, you can automate the process of finding damaged registry entries, links to missing files (for example, calling Networks error) and non-working links within the registry. Before each scanning is automatically created backup copy, allowing you to cancel any changes to one click and protecting you from possible damage to the computer. The most pleasant thing is that the resolution of the registry errors can dramatically increase the speed and performance of the system.

A warning: If you are not an experienced PC user, we do not recommend editing the Windows registry manually. Incorrect use of the registry editor can lead to serious problems and demand reinstalling Windows. We do not guarantee that malfunctions that are the result of the incorrect use of the registry editor can be eliminated. You use the registry editor at your own risk.

Before manually restore windows registryYou must create a backup, exporting a portion of the registry associated with Networks (for example, Microsoft Windows):

Click on the button To begin.
Enter " command." in lock search ... do not press ENTER!
Holding the keys Ctrl-Shift. on the keyboard, click ENTER.
A dialog box for access will be displayed.
Click Yes.
The black box opens with a blinking cursor.
Enter " regedit." and press ENTER.
In the Registry Editor, select the NetWorks-related key (eg. Microsoft Windows) you want to back up.
On the menu File Choose Export.
In the list Save B. Select the folder to which you want to save the Microsoft Windows backup.
In field File name Enter the name of the backup file, for example, "Microsoft Windows backup copy".
Make sure in the field Export range Selected value Selected branch.
Click Save.
The file will be saved with extension.reg..
You now have a backup of your NetWorks-related registry entry.

The following steps with manual editing of the registry will not be described in this article, since it is highly likely to damage your system. If you want to get more information About editing the registry manually, please read the reference below.

Good time, dear readers. Publish the second part. In the current part, the main emphasis is made on network Implementation in Linux(how to set up a network in Linux how to distribute the network in Linux and maintain a network subsystem in Linux in working condition).

TCP / IP Setup in Linux to work in the Ethernet network

For work S. network protocols TCP / IP in Linux is enough only loop interfacebut if you need to combine hosts with each other, naturally, you need to have a network interface, data transmission channels (for example twisted para) perhaps of any network equipment. Also, it is necessary to have the presence of established (, etc.), usually supplied in. You also need to have a network (for example / ETC / HOSTS) and network support.

Network Parameters

Let's start understanding the Linux network mechanisms with manual network configuration, that is, with the case when IP address Network interface static. So, when setting up the network, you must consider and configure the following parameters:

IP address - As already mentioned in the first part of the article, it is a unique address of the machine, in the format of four decimal numbers, separated by points. Usually, when working in local networkSelected from private ranges, for example: 192.168.0.1

Subnet mask - Also, 4 decimal numbers that determine which part of the address refers to the address of the network / subnet, and which is to the address of the host. The subnet mask is a number that folds (in binary form) using a logical and, with an IP address and, resulting in it turns out that the subnet is belong to the address. For example, the address 192.168.0.2 with a mask 255.255.255.0 belongs to the subnet 192.168.0.

Substitute address - Determined by the mask of the subnet. At the same time, no subnets exist for loop interfaces.

Broadcast address - The address used to send broadcast packets, which will receive all subnet hosts. Usually, it is equal to the address of the subnet with the value of the host 255, that is, for the subnet 192.168.0, the broadcast will be 192.168.0.255, similarly, for the subnet 192.168 broadcast will be 192.168.255.255. For loop interfaces there is no broadcast address.

IP address gateway- This is the address of the machine that is the default gateway for communication with the outside world. Gateways can be somewhat if the computer is connected to several networks simultaneously. The gateway address is not used in isolated networks (not connected to global Network), Because this networks have nowhere to send packets outside the network, the same belong to looped interfaces.

Name Server IP Address (DNS - Servers)- address of the server of the transforming host names in the IP address. Usually, provided by the provider.

Network settings files in Linux (configuration files)

To understand the work of the network in Linux, I would definitely advise you to get acquainted with the article "". In general, all linux work based on, which is born when loading OS and puts its descendants, which in turn perform all necessary work, Whether the launch of Bash or Demon. Yes, and all loading Linux is based on, in which the entire sequence of starting small utilities is prescribed with various parameters that are successively started / stop at start-up / stopping the system. Similarly, the Linux network subsystem is launched.

Each Linux distribution is slightly different from the other network initialization mechanism, but the overall picture, I think, after reading it will be clear. If you browse the starting scripts of the network subsystem of any distribution Linux, how to configure the network configuration using configuration fileswill become more or less understandable, for example, Debian (we take this distribution as a basis) the script is responsible for the network initialization. /etc/init.d/networking, reviewing which:

Net-Server: ~ # Cat /etc/init.d/networking ### Begin Init Info # Provides: Networking # Required-Start: MountKernfs $ Local_fs # Required-Stop: $ Local_fs # Should -Start: ifupdown # shald-stop: iFupdown # Default-Start: S # Default-Stop: 0 6 # Short-Description: Raise Network Interfaces. ### end init info path \u003d "/ usr / local / sbin: / usr / local / bin: / sbin: / bin: / usr / sbin: / bin" [-x / sbin / iFup] || EXIT 0. / LIB / LSB / INIT-FUNCTIONS PROCESS_OPTIONS () ([[-E / etc / network / options] || Return 0 log_warning_msg "/ etc / network / options Still EXISTS AND IT WILL BE IGNORED! READ README.DEBIAN OF NETBASE." ) Check_network_file_systems () ([[-E / PROC / MOUNTS] || RETURN 0 if [-e /etc/iscsi/iscsi.initramfs]; Then log_warning_msg "Not Deconfiguring Network Interfaces: Iscsi root is mounted." Exit 0 fi Exec 9<&0 < /proc/mounts while read DEV MTPT FSTYPE REST; do case $DEV in /dev/nbd*|/dev/nd*|/dev/etherd/e*) log_warning_msg "not deconfiguring network interfaces: network devices still mounted." exit 0 ;; esac case $FSTYPE in nfs|nfs4|smbfs|ncp|ncpfs|cifs|coda|ocfs2|gfs|pvfs|pvfs2|fuse.httpfs|fuse.curlftpfs) log_warning_msg "not deconfiguring network interfaces: network file systems still mounted." exit 0 ;; esac done exec 0<&9 9<&- } check_network_swap() { [ -e /proc/swaps ] || return 0 exec 9<&0 < /proc/swaps while read DEV MTPT FSTYPE REST; do case $DEV in /dev/nbd*|/dev/nd*|/dev/etherd/e*) log_warning_msg "not deconfiguring network interfaces: network swap still mounted." exit 0 ;; esac done exec 0<&9 9<&- } case "$1" in start) process_options log_action_begin_msg "Configuring network interfaces" if ifup -a; then log_action_end_msg $? else log_action_end_msg $? fi ;; stop) check_network_file_systems check_network_swap log_action_begin_msg "Deconfiguring network interfaces" if ifdown -a --exclude=lo; then log_action_end_msg $? else log_action_end_msg $? fi ;; force-reload|restart) process_options log_warning_msg "Running $0 $1 is deprecated because it may not enable again some interfaces" log_action_begin_msg "Reconfiguring network interfaces" ifdown -a --exclude=lo || true if ifup -a --exclude=lo; then log_action_end_msg $? else log_action_end_msg $? fi ;; *) echo "Usage: /etc/init.d/networking {start|stop}" exit 1 ;; esac exit 0

you can find several functions checking the presence of connected network file systems ( check_network_file_systems (), check_network_swap ()), as well as checking the existence of some unclear config / etc / network / options (function process_Options ()), and at the very bottom, design case "$ 1" in And in accordance with the parameter entered (START / STOP / FORCE-RELOAD | RESTART or any arc) produces certain actions. Of these most " certain actions", on the example of the argument START, it can be seen that the function is started first process_Options.further goes to the phrase log Configuring Network Interfaces.and team starts IFUP -A.. If you look at MAN ifup, it is clear that this command reads the config from the file / etc / network / interfaces And according to key -a. Runs all interfaces having a parameter aUTO..

The IFUP AND IFDOWN Commands May Be Used to Configure (OR, ReSpectively, Deconfigure) Network Interfaces Based on Interface Definitions in the file / etc / network / interfaces.

-a, --all
If Given to iFup, Affect All Interfaces Marked Auto. Interfaces Are Brought Up in The Order in Which The Are Defined in / etc / Network / Interfaces. If Given to IfDown, Affect All Defined Interfaces. Interfaces Are Brought Down In The Order in Which the Are Currently Listed in the State File. Only Interfaces Defined in / etc / Network / Interfaces Will Be Brought Down.

IP-Server: ~ # This File Describes The Network Interfaces Available On Your System # and How to Activate Them. For more information, See Interfaces (5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface allow-hotplug eth0 iface eth0 inet dhcp allow-hotplug eth2 iface eth2 inet static address 192.168.1.1 netmask 255.255.255.0 gateway 192.168.1.254 broadcast 192.168.1.255

In this config, the string allow-HotPlug. and aUTO. - these are synonyms and interfaces will be raised by the team iFUP -A.. Here, in fact, the entire chain of the network subsystem. Similarly, in other distributions: in Redhat and SUSE network starts a script /etc/init.d/network.. Reviews of it, similarly can be found where the network configuration lies.

/ etc / hosts

This file stores a list IP addresses and corresponding to them (addresses) host names. File format is no different from Mastdayn:

IP-Server: ~ # Cat / etc / hosts # ip host.in.domain host 127.0.0.1 Localhost 127.0.1.1 ip-server.domain.local IP-Server 192.168.1.1 ip-server.domain.local IP-Server

Historically, this file was used instead of the DNS service. Currently, the file can also be used instead of the DNS service, but only provided that on your network the number of machines is measured in units, and not in dozens or hundreds, because in this case you have to control the correctness of this file on each machine.

/ etc / hostname

This file contains NetBIOS host name:

IP-Server: ~ # Cat / etc / hostname ip-server

This file stores the names and addresses of local and other networks. Example:

IP Server: ~ # Cat / etc / Networks default 0.0.0.0 LOOPBACK 127.0.0.0 Link-Local 169.254.0.0 Home-Network 192.168.1.0

When using this file, networks can be managed by name. For example, add a route not route Add. 192.168.1.12 , but route Add..

/etc/nsswitch.conf.

The file determines host search orderNetworks, lines correspond for this setting:

For hosts: Hosts: Files DNS for Networks: Networks: Files

Parameter files. specifies to use the specified files. (/ etc / hosts and / etc / networks respectively), parameter dNS. specifies to use the service dNS..

/etc/host.conf.

The file specifies name resolution parameters for the resolver

IP Server: ~ # Cat /etc/host.conf Multi ON

This file indicates the RESOLV library - return all valid node addresses that met in the / etc / hosts file, and not just the first one.

/etc/resolv.conf.

This file defines the parameters of the network name conversion mechanism in the IP address. Simple language Defines the DNS settings. Example:

IP Server: ~ # cat /etc/resolv.conf NameServer 10.0.0.4 NameServer 10.0.0.1 Search Domain.local

The first 2 lines specify the DNS servers. The third line specifies the search domains. If, when resolving the name, the name will not be an FQDN name, then this domain will substitute in the form of "ending". For example, when executing the Ping Host command, the run address is converted to host.domain.local. The remaining parameters can be read in man risolv.conf. Very often, Linux uses the dynamic generation of this file, using the so-called. programs / sbin / resolvconf. This program is a mediator between services that dynamically providing names for names (for example DHCP Client.) and services that use name server data. In order to use a dynamically generated file /etc/resolv.conf., it is necessary to make this file with a symbolic reference to /etc/Resolvconf/Run/Resolv.conf.. In some distributions, the path may be different, it will be written about it in man Resolvconf..

Network configuration

After reading the main configuration files, you can look at. Above already mentioned the team iFup., iFdown.But these funds are not entirely versatile, let's say in the RH distributions there are no default commands. In addition, a new high-level network management tool appeared in new distributions - which belongs to the iProute package. He (iProute Package) I will be devoted. And in the current post I will not consider it. The commands described below belong.

So, to be confident in the performance of the team in any Linux distribution, it is necessary to use the two main old-handed teams. This is, and ARP. First team (responsible for setting up network interfaces(iP, mask, gateway), second () - routing setup, Third (ARP) - aRP Table Management. I would like to note that the execution of these commands without disabling the standard SystemV startup script for the network subsystem will make changes to the first reboot / restart network service, because If you spoke with brains, you can understand that the script /etc/init.d/networkingat the next launch, re-read the above configs and apply old settings. Accordingly, the output for a permanent settings setting is either the iFConfig command with the corresponding parameters - to enter into, or correct the appropriate network interface configs.

Also, if a team is executed iFconfig with missing parameters (for example, only the IP address), then the rest are complemented automatically (for example, Broadkast Address is added by default with a host address ending at 255 and the default subnet mask is taken 255.255.255.0).

Routing For existing interfaces in modern nuclei, always rises automatically by the kernel. Rather, direct routes to the network according to the IP and subnet settings to which the raised interface are formed automatically, the kernel forces. The Gateway field for such entries shows the output interface address or *. In the old versions of the kernel (the kernel number from which the routes began to rise automatically - I will not tell you) it was necessary to add a route manually.

If there is a need to organize your routes, then you need to use. This command can be added and deleted routes, but again, this will help only before restarting /etc/init.d/networking (or another script responsible for the network in your distribution). So that the routes are added automatically, you must also with the iFConfig command - add commands to add routes to RC.Local, or make the appropriate network interface configumes (for example, in DEB - / etc / Network / Options).

By what rules routes to networks are formed, I'm in

Diagnostics of the Linux network

There are a large number of network diagnostics tools in Linux, often they are very similar to Microsoft utilities. I will consider 3 main network diagnostic utilities, without which it will be problematic to identify problems.

I think that this utility is familiar almost to everyone. The work of this utility is dispatchso-called iCMP packages remote server that will be specified in the command settings, the server returns sent commands, and ping.counts time Required by the Saved Package to reach the server and return. For example:

# Ping Ya.Ru Ping Ya.ru (87.250.251.3) 56 (84) bytes of data. 64 bytes from www.yandex.ru (87.250.251.3): ICMP_SEQ \u003d 1 TTL \u003d 57 TIME \u003d 42.7 MS 64 Bytes from www.yandex.ru (87.250.251.3): ICMP_SEQ \u003d 2 TTL \u003d 57 TIME \u003d 43.2 MS 64 BYETES From www.yandex.ru (87.250.251.3): ICMP_SEQ \u003d 3 TTL \u003d 57 TIME \u003d 42.5 MS 64 Bytes from www.yandex.ru (87.250.251.3): ICMP_SEQ \u003d 4 TTL \u003d 57 TIME \u003d 42.5 MS 64 Bytes from WWW .yandex.ru (87.250.251.3): ICMP_SEQ \u003d 5 TTL \u003d 57 TIME \u003d 41.9 MS ^ C --- ya.ru Ping Statistics --- 5 Packets Transmitted, 5 Received, 0% Packet Loss, Time 4012ms RTT MIN / AVG / MAX / MDEV \u003d 41.922 / 42.588 / 43.255 / 0.500 MS

As can be seen from the above example, ping.displays us a bunch of useful information. Primarily, we found out that we can establish a connection with the host ya.ru(Sometimes they say that the "host ya.ru is available to us"). Secondlywe see that DNS works correctlyBecause the "pingled" name was correctly transformed into IP Address (Ping Ya.R.ru (87.250.251.3)). Further, in field ICMP_SEQ \u003d Specifies the numbering of the packets sent. A number sent to each packet is sequentially assigned and if there will be "failures" in this numbering, it will tell us that the connection with the "pingled" is unstable, as well as may mean that the server to which the packets send overloaded. By meaning time \u003d.we see, how much time package traveled up to 87.250.251.3 and back. Stop the operation of the Ping utility can be keys Ctrl + C.

Same, utility Ping. Interesting what can afford to see where the problems arose. Suppose utility Ping. Displays a message nETWORK NOT REACHABLE (Network is not available)or other similar message. This is most likely talking about the incorrect configuration of your system. In this case, you can send packets on the IP address of the provider to understand where the problem arises (between the local PC or "on"). If you are connected to the Internet via the router, you can send packets on its IP. Accordingly, if the problem is manifested already at this stage, it says about incorrect configuration of the local system, or about the damage to the cable, if the router responds, and there is no provider's server, then the problem is in the provider's communication channel, etc. Finally, if fails ended with the name of the name in IP, you can check the connection over IP if the answers will come correctly, then you can guess that the problem is in DNS.

It should be noted that this utility is not always a reliable tool for diagnosis. Remote server can block answers to ICMP requests.

traceroute.

Simple language, the team is called Tracing route. How can I understand from the name - this utility will show on which route there are packs to host. Traceroute utility Some like ping.But displays more interesting information. Example:

# Traceroute Ya.ru Traceroute to ya.ru (213.180.204.3), 30 Hops Max, 60 Byte Packets 1 243-083-free.kubtelecom.ru (213.132.83.243) 6.408 MS 6.306 MS 6.193 MS 2 065-064-Free .kubtelecom.ru (213.132.64.65) 2.761 MS 5.787 MS 5.777 MS 3 LGW.KUBTELECOM.RU (213.132.75.54) 5.713 MS 5.701 MS 5.636 MS 4 kubtelecom-lgw.krasnodar.gldn.net (194.186.6.177) 81.430 MS 81.581 MS 81.687 MS 5 Cat26.Moscow.gldn.net (194.186.118) 47.789 MS 47.888 MS 48.011 MS 6 213.33.201.230 (213.33.201.230) 43.322 MS 41.783 MS 41.106 MS 7 carmine-red-vlan602.yandex.net (87.250. 242.206) 41.199 MS 42.578 MS 42.610 MS 8 www.yandex.ru (213.180.204.3) 43.185 MS 42.126 MS 42.679 MS

As you can see, you can trace the route from the provider router 243-083-Free.Kubtelecom.ru (213.132.83.243) (South of Russia) to the final host in www.yandex.ru (213.180.204.3) in Moscow.

dig

This utility sends requests to DNS servers and returns information about the specified domain. Example:

# Dig @ ns.kuban.ru roboti.ru;<<>\u003e Dig 9.3.6-P1<<>\u003e @ ns.kuban.ru roboti.ru; (1 Server Found) ;; Global Options: Printcmd ;; Got Answer: ;; - \u003e\u003e Header.<<- opcode: QUERY, status: NOERROR, id: 64412 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0 ;; QUESTION SECTION: ;roboti.ru. IN A ;; ANSWER SECTION: roboti.ru. 448 IN A 72.52.4.90 ;; AUTHORITY SECTION: roboti.ru. 345448 IN NS ns1.sedoparking.com. roboti.ru. 345448 IN NS ns2.sedoparking.com. ;; Query time: 102 msec ;; SERVER: 62.183.1.244#53(62.183.1.244) ;; WHEN: Thu Feb 17 19:44:59 2011 ;; MSG SIZE rcvd: 94

Dig command sent request server DNS. - nS.KUBAN.RU. (@ Ns.Kuban.ru. - This option is not necessary, in this case, the source of DNS information will be taken from the configuration of your system) about the domain name Roboti.ru.. As a result, he received an answer in which we can see in the section Answer Section. Information about the IP addresses of the domain in the section AUTHORITY SECTION Information about the so-called. authoritative DNS servers. The third line from below tells us what server provided the answer.

Other diagnostic utilities

ping, Dig and other diagnostic utilities with parameters can be found in post.

Connecting a new network card

Connecting and launching a new network card comes down to performing a few steps:

1. Physical Card Connection

3. View output to detect a new network card system:

Let's see the output Before connecting a new card:

Server: ~ # Dmesg | GREP ETH [4.720550] E1000: ETH0: E1000_PROBE: Intel (R) Pro / 1000 Network Connection [5.130191] E1000: ETH1: E1000_Probe: Intel (R) Pro / 1000 Network Connection [15.285527] E1000: ETH2: E1000_WatchDog: Nic Link is Up 1000 MBPS Full Duplex, Flow Control: RX [15.681056] E1000: ETH0: E1000_WatchDog: Nic Link Is Up 1000 MBPS Full Duplex, Flow Control: RX

in the output it is clear that the system has 2 network cards ETH1 and ETH2. We connect the third and see the conclusion:

Server: ~ # Dmesg | GREP ETH [4.720513] E1000: ETH0: E1000_PROBE: Intel (R) Pro / 1000 Network Connection [5.132029] E1000: ETH1: E1000_PROBE: Intel (R) Pro / 1000 Network Connection [5.534684] E1000: ETH2: E1000_PROBE: Intel (R ) PRO / 1000 Network Connection [39.274875] udev: renamed network interface eth2 to eth3 [39.287661] udev: renamed network interface eth1_rename_ren to eth2 [45.670744] e1000: eth2: e1000_watchdog: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX [46.237232] E1000: ETH0: E1000_WatchDog: Nic Link is up 1000 MBPS Full Duplex, Flow Control: Rx [96.977468] E1000: ETH3: E1000_WatchDog: Nic Link is up 1000 MBPS Full Duplex, Flow Control: RX

IN dmesg.we see that a new networking appeared is ETH3, which is actually ETH2, but renamed UDEV devices to ETH3, and ETH2 is actually renamed Eth1 (we will talk about UDev in a separate post). The appearance of our new network in DMesg We say that network card supportedkernel and correct determined. It remains for small - set up a new interface in / etc / network / interfaces(Debian), because this card was not initialized by the starting script /etc/init.d/network.. iFconfigthis card sees:

Server: ~ # Ifconfig ETH3 ETH3 LINK ENCAP: Ethernet Hwaddr 08: 00: 27: 5F: 34: AD INET6 ADDR: Fe80 :: A00: 27FF: FE5F: 34AD / 64 Scope: Link Up Broadcast Running Multicast MTU: 1500 Metric: 1 RX Packets: 311847 Errors: 0 Dropped: 0 Overruns: 0 Frame: 0 TX Packets: 126 Errors: 0 Dropped: 0 Overruns: 0 Carrier: 0 Collisions: 0 TXQueuelen: 1000 RX Bytes: 104670651 (99.8 MIB) TX Bytes: 16184 (15.8 KIB)

but again - it does not configure. How to configure the network card mentioned above.

Summary

I think today is all. When I started writing this article, I thought that I would do in one post, but he turned out to be high. Therefore, it was decided to smash an article into two. Total, I tried to set out, not a step-by-step hoatch on setting up the network, but to set out the principle and explain the understanding of how the network in Linux is started and running. I really hope that I managed it. I will be glad to your comments and additions. Over time, I will complement an article.

When it comes to computer networks, it is often possible to hear the mention of NFS. What does this abbreviation mean?

This is a protocol of a distributed file system, originally developed by Sun Microsystems in 1984, allowing the user on the client computer to access files through the network, like access to the local storage. NFS, like many other protocols, is based on the Open Network Computing Remote Procedure Call system (ONC RPC).

In other words, what is NFS? This is an open standard defined in Request for Comments (RFC), which allows you to implement a protocol.

Versions and variations

The inventor used only the first version for its own experimental purposes. When the developer team added significant changes to the initial NFS and released it outside the authorship of the Sun, they marked the new version as v2 so that you can test the interaction between distributions and create a backup option.

NFS V2.

Version 2 originally worked only on the User Datagram Protocol (UDP) protocol. Its developers wanted to save the server side without blocking implemented outside the main protocol.

The interface of the virtual file system allows you to perform modular implementation reflected in the simple protocol. By February 1986, solutions were demonstrated for operating systems such as System V Release 2, DOS and VAX / VMS using EUNICE. NFS V2 allowed to read only the first 2 GB of the file due to 32-bit restrictions.

NFS V3.

The first offer to develop NFS version 3 in Sun Microsystems was voiced shortly after the release of the second distribution. The main motivation was an attempt to mitigate the problem of performance of a synchronous recording. By July 1992, practical improvements made it possible to solve many shortcomings of NFS version 2, while leaving only insufficient support for files (64-bit sizes and file offset).

support for 64-bit sizes and file displacements for data processing of more than 2 gigabytes (GB);
support for asynchronous recording on the server to increase productivity;
additional file attributes in many answers to avoid the need to re-extract them;
rEADDIRPLUS operation for data and attributes along with file names when scanning directory;
many other improvements.

During the introduction of version 3, TCP support as a transport level protocol began to increase. Using TCP as a data transfer tools made using NFS via WAN, has become allowed to transmit large file sizes to view and write. Thanks to this, the developers were able to overcome the limits of restrictions in 8 KB, imposed by the user datagram protocol (UDP).

What is NFS V4?

Version 4, developed under the influence of the Endra File System (AFS) and the Server Message Block (SMB, also called CIFS), includes an increase in performance, provides better security and enters the protocol in compliance with the established conditions.

Version 4 has become the first distribution plan developed in the target group of the Internet Engineering Task Force (IETF) after Sun Microsystems has conveyed to the development of protocols to third-party specialists.

NFS version 4.1 is aimed at providing support for the protocol to use cluster server deployments, including the ability to provide scalable parallel access to files distributed between multiple servers (PNFS extension).

The newest File System Protocol - NFS 4.2 (RFC 7862) - was officially released in November 2016.

Other extensions

With the development of the standard, the corresponding tools for working with it appeared. Thus, WebNFS, extension for versions 2 and 3, allows the network access protocol to file systems easier to integrate into web browsers and activate work through firewalls.

The various protocols of third-party groups have also become associated with NFS. Of these, the most famous are:

Network Lock Manager (NLM) with byte protocol support (added to support UNIX System V files);
remote Quota (RQUOTAD), which allows NFS users to view data storage quotas on NFS servers;
NFS via RDMA - adaptation NFS, which uses remote direct memory access (RDMA) as a means of transmission;
NFS-Ganesha is a NFS server that works in user space and supporting CEPHFS FSAL (file system abstraction) using libcephfs.

Platform

Network File System is often used with UNIX operating systems (such as Solaris, AIX, HP-UX), Apple MacOS and UNIX-like OS (such as Linux and FreeBSD).

It is also available for platforms such as ACORN RISC OS, OpenVMS, MS-DOS, Microsoft Windows, Novell NetWare and IBM AS / 400.

Alternative file remote access protocols include a server message block (SMB, also called CIFS), Apple Transmission Protocol (AFP), NetWare Basic Protocol (NCP) and OS / 400 Server File System (QFilesVR.400).

This is due to the requirements of NFS, which are focused mostly on UNIX-like "shells".

In this case, the SMB and NetWare (NCP) protocols are used more often than NFS, in systems running Microsoft Windows. AFP is most widespread in Apple Macintosh platforms, and QFilesVR.400 is most often found in OS / 400.

Typical implementation

Assuming a typical Script in the UNIX style, in which one computer (client) needs access to data stored on another (NFS server):

The server implements the default NETWORK File System processes as NFSD to make their data publicly available to customers. The server administrator determines how to export the names and parameters of the directories, usually using the configuration file / etc / exports and the ExportFS command.
Server Security Administration ensures that it will be able to recognize and approve a proven client. The configuration of its network ensures that the relevant customers can negotiate with it through any firewall system.
The client machine requests access to exported data, as a rule, by issuing an appropriate command. She requests the server (rpcbind) that uses the NFS port, and subsequently connects to it.
If everything happens without errors, users on the client machine will be able to browse and interact with the installed file systems on the server within the allowed parameters.

Attention should also be paid to the fact that the automation of the Network File System process can also occur - possibly using ETC / FSTAB and / or other similar means.

Development today

By the 21st century, DFS and AFS competitors did not reach any major commercial success compared to Network File System. IBM, who had previously acquired all commercial rights to the above technologies, donated to the most of the source AFS source code to the Community of Free Software Developers in 2000. The Open AFS project exists today. In early 2005, IBM announced the completion of Sales AFS and DFS.

In turn, in January 2010, Panasas suggested NFS V 4.1 based on technology that allows you to improve the possibilities of parallel access to data. Network File System V 4.1 protocol Specifies the method of separating the metadata of the file system from the location of certain files. Thus, it goes beyond the simple division of names / data.

What is NFS this version in practice? The above feature distinguishes it from a traditional protocol that contains file names and their data under one binding to the server. When implementing Network File System V 4.1, some files can be distributed between multi-numeral servers, but the client's participation in the separation of metadata and data is limited.

When implementing the fourth distribution, the NFS server protocol is a set of server resources or components; It is assumed that they are controlled by the metadata server.

The client still refers to one metadata server to bypass or interact with namespace. When it moves files to the server and from it, it can directly interact with the data set belonging to the NFS group.

What is the practical use of the file / etc / networks? As I understand it, in this file you can specify network names. For example:

[Email Protected]: ~ # Cat / etc / Networks default 0.0.0.0 LOOPBACK 127.0.0.0 Link-Local 169.254.0.0 Google-DNS 8.8.4.4 [Email Protected]:~#

However, if I try to use this network name, for example, in the IP utility, it does not work:

[Email Protected]: ~ # IP Route Add Google-DNS VIA 104.236.63.1 DeV ETH0 Error: An Inet Prefix Is Expected Rather Than "Google-DNS". [Email Protected]: ~ # IP Route Add 8.8.4.4 Via 104.236.64.1 DeV Eth0 [Email Protected]:~#

What is the practical use of the file / etc / networks?

2 Solutions Collect Form Web for "Practical use of a file / etc / networks"

As written on the manual page, the / etc / networks file must describe symbolic names for networks. With the network it means a network address with a tail on the end. Only simple class A, B or C are supported.

In your example, Google-DNS is incorrect. This is not a network A, B or C. This is the ratio of IP-Address-hostname, so it belongs to / etc / hosts. In fact, the Default record also does not match.

Suppose you have an IP address 192.168.1.5 from your corporate network. The entry in / etc / network could be as follows:

Corpname 192.168.1.0.

When using such utilities such as Route or Netstat, these networks are translated (if you do not suppress the resolution with the -N flag). The routing table may look like this:

Kernel IP Routing Table Destination Gateway Genmask Flags Metric Ref Use IFACE DEFAULT 192.168.1.1 0.0.0.0 UG 0 0 0 0 ETH0 CORPNAME * 255.255.255.0 U 0 0 0 ETH0

The IP command never uses the node name to enter, so your example is unlikely to matter. You also put the name of the host in / etc / networks, and not in the network name!

Records from / etc / networks are used by tools that are trying to convert numbers in names, for example, the (outdated) route command. Without a suitable record, it shows:

# ROUTE KERNEL IP ROUTING TABLE DESTINATION GATEWAY GENMASK FLAGS METRIC REF USE IFACE DEFAULT 192.168.1.254 0.0.0.0 UG 0 0 0 ETH0 192.168.0.0 * 255.255.254.0 U 0 0 0 ETH0

If you can now add the Mylocalnet line 192.168.0.0 in / etc / networks:

# ROUTE KERNEL IP Routing Table Destination Gateway Genmask Flags Metric Ref Use IFACE DEFAULT 192.168.1.254 0.0.0.0 UG 0 0 0 ETH0 Mylocalnet * 255.255.254.0 U 0 0 0 ETH0

In practice, it is never used.

GO!

File hosts. Sets the match between the IP server and the site domain. The request to this file takes priority before referring to DNS servers. Unlike DNS, the contents of the file is controlled by the computer administrator.

To date, a large number of malicious programs use the file hosts. To block access to websites of popular portals or social networks. Often, instead of blocking sites, malware redirects the user to pages, externally similar to popular resources (social networks, postal services, etc.), where the inattentive user enters the credentials in this way to attackers. Also, it is possible to block access to the websites of anti-virus software developers.

Hosts file location

By default file hosts. Located here C: \\ Windows \\ System32 \\ DRIVERS \\ ETC The file has no extension, but you can open it with a notepad. To change the contents of the file in Notepad, you must have administrator rights.

To view the file hosts. Open menu Start, Select Perform, Enter the command

and click OK

So the file should look like hosts. default.

If there are type records in the file 127.0.0.1 Odnoklassniki.ru. 127.0.0.1 vkontakte.ru. or addresses of your sites that you cannot go, then for starters check your computer on "malware", and then restore the file hosts.

Restore the contents of the HOSTS file by default

Open menu Start, Select Perform, Enter the command
% Systemroot% \\ System32 \\ Drivers \\ etc

and click OK.
Rename Hosts file to hosts.old..
Create a new file hosts. default. To do this, follow the steps below.

Right-click in the folder % Windir% \\ System32 \\ Drivers \\ etc, Select CreateClick Element Text Document, Enter your name hosts. and press the key Input.
Press the button Yesto confirm that the file name will not have an extension TXT..
Open a new file hosts. In a text editor. For example, open the file in the program " Notebook".
Copy the text below.

#
#

# Space.
#

#
# FOR EXAMPLE:
#

# 127.0.0.1 Localhost
# :: 1 Localhost

Save and close the file.

You can edit the file hosts. And in notepad, remove unnecessary lines, or add your own. To do this, you need to run Notebook In mode Administrator.

How to run standard Windows programs see

In this article, we will consider the method of cleaning this file with the tools of the Windows operating system itself without downloading special programs.

This article is written solely on the basis of the personal experience of the author and co-authors. All the above tips you perform at your own risk. For the consequences of your actions, the author and the site administration are not responsible.

Before you start cleaning the file, you must do the following operations ( before!):

if the antivirus program is not installed, find and install any antivirus program to choose from;
it is necessary to update the anti-virus bases as of the current day;
carry out a complete check of the system for malicious content (in some cases it may be necessary to check in safe mode or with Live CD / DVD);
after checking the antivirus program, disable antivirus protection during the cleaning of the HOSTS file (some antiviruses block changes).

Attention! Present manual for cleaning the HOSTS file ineffective in the "infected" computer. Previously, you should cure the system from viruses and then proceed to correcting the HOSTS file.

If you independently did not change the location of the folder with the Hosts file, then I recommend to start the registry key to return to the default value. To do this, open the empty notepad, insert the text below and save the file named hostsdir.reg. on the desktop.

Windows Registry Editor Version 5.00 "Databasepath" \u003d Hex (2): 25.00,53.00,00,00,00,63,00,00,00,00,00,00,00,00,00,00,00,00,00, 00.52,00,6F, 00, 6F, \\ 00.74,00,25,00,5c, 00,53,00,79.00,00,00,00,00,00,00,00,00,00,00,00,00,6,00,00,5 00, \\ 64.00,72.00,69.00.76,00.65.00.72,00.73,00,5c, 00.65.00.74.00.63.00,00,00, 00.

The text should begin without spaces and empty lines, after the line "Windows Registry Editor Version 5.00" there must be one empty string, after all the text it is also necessary to put an empty string. In a double-byte sixteenth-round file (hex (2) :), the string "% Systemroot% \\ System32 \\ Drivers \\ etc" is encoded.

After saving the file, close the notepad, locate the file on the desktop hostsdir.reg. And double click on it. The system to notify you that an attempt is made to make changes to the registry and requests your consent. Answer "Yes", after which the change in the registry will be made.

If the system is reporting that access or change in the registry is prohibited, it means that you do not have administrative rights in the system or your system requires more careful attention, the use of special treatment programs.

Click (or the same: Click the keyboard key Win + R.)

A window will appear Running program

In field Open We enter the string:

NotePad% Systemroot% \\ System32 \\ Drivers \\ ETC \\ HOSTS

(just copy the following command text in the field Openwindow Running programs). Click OK

We see on the screen notepad with approximately similar content:

It is also found that some sly pests are prescribed their ill-purpose addresses outside the notebook window. Always check if you have a scroll bar on the side and always scroll through the window to the end of the file.

Clean the editor's window fully (click Ctrl + A and Delete) and copy one of the following texts depending on the version of your operating system.

# Copyright (C) 1993-2009 Microsoft Corp. # # This is a sample hosts file Used by Microsoft TCP / IP for Windows. # # This File Contains The Mappings of IP Addresses to Host Names. Each # Entry Should Be Kept On An Individual Line. The IP Address Should # Be Placed in the CorreSponding Host Name. # The IP Address and The Host Name Should Be Separated by At Least One # Space. # # ADDITIONALLY, COMMENTS (Such As These) May Be Inserted on Individual # Lines or Following the Machine Name denoted by A "#" Symbol. # # For example: # # # # # For example: # # 102.54.94.97 rhino.acme.com # Source Server # 38.25.63.10 x.acme.com # X Client Host # Localhost Name Resolution Is Handled Within DNS ItSelf. 127.0.0.1 Localhost.

# Copyright (C) 1993-2006 Microsoft Corp. # # This is a sample hosts file Used by Microsoft TCP / IP for Windows. # # This File Contains The Mappings of IP Addresses to Host Names. Each # Entry Should Be Kept On An Individual Line. The IP Address Should # Be Placed in the CorreSponding Host Name. # The IP Address and The Host Name Should Be Separated by At Least One # Space. # # ADDITIONALLY, COMMENTS (Such As These) May Be Inserted on Individual # Lines or Following the Machine Name denoted by A "#" Symbol. # # # For example: # # # # # For example: # # 102.54.94.97 rhino.acme.com # Source Server # 38.25.63.10 x.acme.com # X Client Host 127.0.0.1 Localhost :: 1 Localhost

# Copyright (C) 1993-2006 Microsoft Corp. # # This is a sample hosts file Used by Microsoft TCP / IP for Windows. # # This File Contains The Mappings of IP Addresses to Host Names. Each # Entry Should Be Kept On An Individual Line. The IP Address Should # Be Placed in the CorreSponding Host Name. # The IP Address and The Host Name Should Be Separated by At Least One # Space. # # ADDITIONALLY, COMMENTS (Such As These) May Be Inserted on Individual # Lines or Following the Machine Name denoted by A "#" Symbol. # # For example: # # 102.54.94.97 rhino.acme.com # Source Server # 38.25.63.10 x.acme.com # X Client Host # Localhost Name Resolution Is Handle Within Dns Itself. # 127.0.0.1 Localhost # :: 1 Localhost

Please note most of the rows begin with the sign #. This sign means the beginning of the comment and the entire text until the end of the line system is not perceived. In connection with this circumstance, only the last string is important in texts for Windows XP and Windows Vista, and the text can be completely empty for Windows 7, 8 and 10.

Then we save the changes made, close the notebook and try to open previously blocked sites.

Attention! The site administration as an alternative does not recommend to delete the ETC folder where the HOSTS file contains. This can lead to the collapse of the system.

After successful file saving, there may be the following options:

everything has come to normal and previously blocked sites open normally;
sites continue to be blocked or open third-party resources. This means that the system has an active Trojan, which, with a certain periodicity, checks the contents of the HOSTS file and changes it.

If, after rebooting the system, everything returned to the same state of blocking favorite sites, which means you need to return to the beginning of the article and choose another antivirus to check the system.

There are also cases when after making changes, you cannot save the file. Open the system command line (Start - standard - command line or Win + R - CMD - OK) and in turn I enter the command below:

CD% Systemroot% \\ System32 \\ Drivers \\ etc attrib -s -h -r hosts notepad hosts

If you cannot save the file in Windows systems (including Windows XP, if you entered the system with a limited account), you need to log in to the administrator account system or run a notebook on behalf of the administrator and edit the file. For more information, this operation is specified in the article on our website. It is not possible to save the HOSTS file.

If nothing helped !!!

Download the file attached below and run. The file downloaded from the Microsoft website and does not contain malicious content.

Attention! Attached file is not an antivirus program! It only automatically resets the contents of the HOSTS file before the default content is described for manual editing in the article.

Main Writer on Technology

Someone sent you an ETC file by e-mail, and you do not know how to open it? Maybe you found the ETC file on your computer and you are interested in what is the file? Windows can tell you that you cannot open it, or, in the worst case, you may encounter an appropriate error message associated with the ETC file.

Before you can open the ETC file, you need to find out how the file has the extension of the ETC file.

Tip: Incorrect etc File Association Errors Can Be a Symptom of Other Underlying Issues Within Your Windows Operating System. These Invalid Entries Can Also Produce Associated Symptoms Such As Slow Windows Startups, Computer Freezes, and Other PC Performance Issues. Theraefore, IT Highly Recommended That You Scan Your Windows Registry for Invalid File Associations and Other Issues Related To a Fragmented Registry.

Answer:

ETC files have Uncommon Files, which is predominantly associated with EtreppID Compressed File.

ETC files are also associated with Seismograph File and FileViewPro.

Other file types can also use the ETC file extension. If you know any other file formats that use the ETC file extension, please contact us so that we can appropriately update our information.

How to open your ETC file:

The fastest and easiest way to open your ETC file is twice the mouse over it twice. In this case, the Windows system itself will select the desired program to open your ETC file.

In case your ETC file does not open, it is very likely that the necessary application program is not installed on your PC to view or edit files with ETC extensions.

If your PC opens the ETC file, but in the wrong program, you will need to change the settings of the file association in your Windows registry. In other words, Windows associates ETC file extensions with an incorrect program.

Install Optional Products - FileViewPro (Solvusoft) | | | |

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After a few seconds, you exactly recognize the type of your ETC file, the application associated with the file, the name of the user's file, file protection status and other useful information.

To start a free file analysis, simply drag your ETC file inside the dotted line below or click "View My Computer" and select File. The ETC file analysis report will be shown right in the browser window.

Drag the ETC file here to start analysis.

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Please also check my file for viruses

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What is your HOSTS file?
Purpose of this system file - assigning certain addresses of certain IP sites.
This file is very loved by all kinds of viruses and malware in order to register their data in it or simply replace it.
The result of these actions may be the signs of the "insertion" of the site into browsers, which will ask to send SMS when opening a browser or blocking various sites, at the discretion of the creators of the virus.

Where is the HOSTS file in Windows?
For different versions of Windows, the location of the Hosts file is a bit different:

Windows 95/98 / Me: Windows \\ Hosts
Windows NT / 2000: WinNT \\ System32 \\ Drivers \\ ETC \\ HOSTS
Windows XP / 2003 / VISTA / SEVEN (7) / 8: Windows \\ System32 \\ DRIVERS \\ ETC \\ HOSTS

Moreover, the end hosts., it is already a final file, not a folder. He has no.

How should the correct HOSTS file look like?
The contents of the HOSTS file is as little different for different versions of Windows, but not particularly. It "written" in English for what it is needed and how to make exceptions to bring one example. All lines starting with the mark # mean that they are commented and do not affect the file.
The content of the original HOSTS file for Windows XP:

# Space.
#

#
# FOR EXAMPLE:
#

127.0.0.1 Localhost.

The content of the original HOSTS file for Windows Vista:

# Copyright (C) 1993-2006 Microsoft Corp.
#
# This is a sample hosts file Used by Microsoft TCP / IP for Windows.
#
# THIS File Contains The Mappings of IP Addresses to Host Names. Each.
# Entry Should Be Kept On An Individual Line. The IP Address Should
# Be Placed in the Corresponding Host Name # Be Placed In The First Column Followed by the CRESPONDING HOST NAME
# The IP Address and The Host Name Should Be Separated by At Least One
# Space.
#
# Additionally, Comments (Such As These) May Be Inserted on Individual
# Lines or Following The Machine Name Denoted by A "#" Symbol.
#
# FOR EXAMPLE:
#
# 102.54.94.97 rhino.acme.com # Source Server
# 38.25.63.10 x.acme.com # x client host
127.0.0.1 Localhost :: 1 Localhost

The content of the original HOSTS file for Windows 7:

# Copyright (C) 1993-2009 Microsoft Corp.
#
# This is a sample hosts file Used by Microsoft TCP / IP for Windows.
#
# THIS File Contains The Mappings of IP Addresses to Host Names. Each.
# Entry Should Be Kept On An Individual Line. The IP Address Should
# Be Placed in the Corresponding Host Name # Be Placed In The First Column Followed by the CRESPONDING HOST NAME
# The IP Address and The Host Name Should Be Separated by At Least One
# Space.
#
# Additionally, Comments (Such As These) May Be Inserted on Individual
# Lines or Following The Machine Name Denoted by A "#" Symbol.
#
# FOR EXAMPLE:
#
# 102.54.94.97 rhino.acme.com # Source Server
# 38.25.63.10 x.acme.com # x client host
# Localhost Name Resolution Is Handle Within DNS ItSelf.
# 127.0.0.1 Localhost
# :: 1 Localhost

The content of the original HOSTS file for Windows 8:

# Localhost Name Resolution Is Handled Within DNS ItSelf.
# 127.0.0.1 Localhost
# :: 1 Localhost

As you can verify, in the content of the HOST file for different versions of Windows, there are no special differences.

How to open and change the HOSTS file?
Hosts file can be standard Windows Notepad.
Here, probably, the most interesting part of the article.
First of all, you need to understand, why should I change this file at all? Yes, in order to prohibit access to certain sites. Thus, by changing this file and speaking the address of the site into it, the user will not be able to go on it anyway.
In order to change the HOSTS file, it is desirable to open it on behalf of the administrator () by clicking the PCM on the file and selecting "Run from the administrator name". Or open a notebook and already open the file in it.

For speed, you can simply click the Start button and select Run item ( wIN.+r.) () And enter in the string:

notePad% WinDir% \\ System32 \\ Drivers \\ etc \\ hosts

As a result, this file will appear in the notebook.

In order to be abloking access to the site (Suppose it will be test.ru), you just need to add a string with this site at the bottom:

127.0.0.1 Test.ru.

As a result, the file will be such a content:

# Copyright (C) 1993-1999 Microsoft Corp.
#
# This is a sample hosts file Used by Microsoft TCP / IP for Windows.
#
# THIS File Contains The Mappings of IP Addresses to Host Names. Each.
# Entry Should Be Kept On An Individual Line. The IP Address Should
# Be Placed in the Corresponding Host Name # Be Placed In The First Column Followed by the CRESPONDING HOST NAME
# The IP Address and The Host Name Should Be Separated by At Least One
# Space.
#
# Additionally, Comments (Such As These) May Be Inserted on Individual
# Lines or Following The Machine Name Denoted by A "#" Symbol.
#
# FOR EXAMPLE:
#
# 102.54.94.97 rhino.acme.com # Source Server
# 38.25.63.10 x.acme.com # x client host

# This Hosts File Created by Dr.Web Anti-Rootkit API

# 127.0.0.1 Localhost
# :: 1 Localhost
127.0.0.1 Test.ru.

Each new site you want to block, you need to start with a new line and prescribe, not forgetting a local IP address 127.0.0.1

Also, to edit the HOSTS file, there is a program Hosts Editor, Download and read the description with.
The principle of work is that it helps edit the HOSTS file.
From the screen below it is clear the principle of its work, everything is done in a couple of clicks. Adding is carried out by pressing +.

After editing, do not forget to click on the save button (2 "Save Changes" button to the left of the "+" button).

Also change this file can also be for good purposes, for example accelerate Site Downloads.
How it works?
When entering the site, you see his domain name that has letters. But all sites on the Internet have an IP address, and the names are already assigned to the use of DNS. I will not go into the details of this process, the article is not about it. But here you need to know what the hosts file takes priority when accessing sites, and only after it is requested to DNS.
In order to speed up the site load, you need to know its IP address and domain.
The site's ip address can be found using various services, such as or.
Domain is the name of the site.
For example, you will speed up the download of this site, where you read the article, explicitly specify the IP address and domain file.
Then the line added will be:

91.218.228.14 Site

This speeds up loading the page in a couple of seconds, and sometimes can access if you cannot enter the site with standard tools.

Still with it is possible redirect to another site using Hosts file.
To do this, you need to know the IP address of the site and its domain (as in the case described above), then the string added will be like this:

91.218.228.14 Test.ru.

And now, after entering the Test.ru browser line to the address bar, you will be redirected to the site specified in the IP address ..

If you want to clear Hosts fileYou can do it, just deleting the contents and insert the original text into it, from the description above (under spoilers).

Some nuances in the Hosts file:

Always check if you have a scroll bar on the side and always scroll to the Donom window. This is due to the fact that some viruses are prescribed to the area hidden outside the window.

In some cases, usually if it is not possible to save the file, you need to enter the administrator account.

Sometimes, due to viruses, this file can be hidden. Read the article.

In the two described methods (redirection and acceleration) there may not be the desired result. The fact is that there may be several sites on one IP address, it is especially true for external IP addresses that provide services.

Due to the fact that viruses like this file, its attributes can be changed on Hidden and Read-only.

Check the file attributes if you cannot save the HOSTS file.

Thus, you can easily block access to sites in Windows by editing Hosts file.

Hosts file is a fairly vulnerable area in the Windows operating system. This file becomes the target number one almost for all virus and trojans, which can be infected with the computer. In this article, we will tell you what the Hosts file is where it is, for which it is used and how to restore it after infection with viruses.

The task of this file store the list of domains and the corresponding IP addresses. The operating system uses this list to convert domains to IP addresses and vice versa.

Each time you enter the address in the address bar of the browser you need a site, a request for a domain conversion to the IP address occurs. Now this transformation is executed by the service called DNS. But, at the dawn of the Internet hosts, the file was the only opportunity to associate the character name (domain) with a specific IP address.

Even now, this file has a direct impact on the conversion of symbolic names. If you add an add an entry to hosts to a domain IP address, then such a record will work perfectly. This is exactly what the developers of viruses, Trojans and other malicious programs are used.

As for the file structure, the HOSTS file is an ordinary text file extension beser. That is, this file is not called not, hosts.txt, but just hosts. To edit it, you can use the usual text editor notepad (NotePad).

The standard HOSTS file consists of several lines that start with the "#" symbol. Such lines are not taken into account by the operating system and are simply comments.

Also in the standard HOSTS file there is a record "127.0.0.1 localhost". This record means that when accessing the symbolic name Localhost, you will appear to your own computer.

Machinations with Hosts File

There are two classic ways to benefit from making changes to the Hosts file. Firstly, you can block access to sites and antivirus software servers.

For example, infecting the computer, the virus adds In the hosts file such entry: "127.0.0.1 kaspersky.com." When you try to open the site kaspersky.com, the operating system will connect to the IP address 127.0.0.1. Naturally, this is an incorrect IP address. This leads to Access to this site is completely blocked. As a result, the user of an infected computer cannot download antivirus or updates of antivirus bases.

In addition, developers can use another reception. By adding entries to the Hosts file, they can redirect users to a fake site.

For example, infecting the computer, the virus adds such an entry to the HOSTS file: "90.80.70.60 Vkontakte.ru." Where "90.80.70.60" is an IP address of the attacker's server. As a result, when trying to go to the well-known site, the user hits the site that looks exactly also, but is on someone else's server. As a result of such actions, fraudsters can get logins, passwords and other personal information of the user.

So in case of any suspicion of infection with the virus or on the site submenu, the first thing you need to check the hosts file.

Where is the hosts file

Depending on the version of the Windows operating system, the HOSTS file can be solved in various folders. For example, if you use Windows XP, Windows Vista, Windows 7 or Windows 8, the file is in the Windows \\ System32 \\ Drivers \\ ETC \\ ETC folder.

In Windows NT and Windows 2000 operating systems, this file lies in the Winnt \\ System32 \\ Drivers \\ ETC \\ ETC folder.

In completely ancient versions of the operating system, for example, in Windows 95, Windows 98 and Windows ME, this file can be found simply in the Windows folder.

Restore Hosts file

Many users who are suspended hacking are interested in where you can download hosts file. However, you do not need to search and download the original Hosts file. It can be corrected independently, for this you need to open a text editor and delete everything except the line except "127.0.0.1 Localhost". This will unlock access to all sites and update the antivirus.

Consider in more detail the HOSTS file recovery process:

Open the folder in which this file is located. In order not to wander around the catalogs for a long time in search of the desired folder you can use a little cunning. Press the Windows + R keys combination in order to open menu "Run" In the window that opens, enter the command "% Systemroot% \\ System32 \\ Drivers \\ etc" and click OK.
After your folder opens in front of which the HOSTS file is a backup of the current file. In case something goes wrong. If the hosts file exists, simply rename it to hosts.old. If the HOSTS file is not at all in this folder, then this item can be skipped.
Create a new empty hosts file. To do this, right-click in the ETC folder and select item. "Create a text document".
When the file is created, it must be renamed to hosts. When renaming the window will appear in which will be a warning that the file will be saved without expansion. Close the window with a warning by pressing the OK button.
After the new hosts file is created, it can be edited. To do this, open the file using a notepad program.
Depending on the version of the operating system, the contents of the standard hosts file may differ.
For Windows XP and Windows Server 2003, add "127.0.0.1 Localhost".
Windows Vista, Windows Server 2008, Windows 7 and Windows 8 need to add two lines: "127.0.0.1 Localhost" and ":: 1 Localhost".