Difference between revisions of "Proxy server"

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(on/off proxy script with argument and interactive mode)
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If the proxy environment variables are to be made available to all users and all applications, the above mentioned export commands may be added to a script, say "proxy.sh" inside /etc/profile.d/. The script has to be then made executable. This method is helpful while using a Desktop Environment like [[Xfce]] which does not provide an option for proxy configuration. For example, [[Chromium]] browser will make use of the variables set using this method while running XFCE.  
 
If the proxy environment variables are to be made available to all users and all applications, the above mentioned export commands may be added to a script, say "proxy.sh" inside /etc/profile.d/. The script has to be then made executable. This method is helpful while using a Desktop Environment like [[Xfce]] which does not provide an option for proxy configuration. For example, [[Chromium]] browser will make use of the variables set using this method while running XFCE.  
 
   
 
   
Alternatively you can automate the toggling of the variables by adding a function to your .bashrc (thanks to Alan Pope)
+
Alternatively you can automate the toggling of the variables by adding a function to your .bashrc (thanks to Alan Pope for original script idea)
 
  <nowiki>
 
  <nowiki>
 
function proxy_on() {
 
function proxy_on() {
 
     export no_proxy="localhost,127.0.0.1,localaddress,.localdomain.com"
 
     export no_proxy="localhost,127.0.0.1,localaddress,.localdomain.com"
  
if (( $# > 0 )); then
+
    if (( $# > 0 )); then
valid=$(echo $@ | sed -n 's/\([0-9]\{1,3\}.\)\{4\}:\([0-9]\+\)/&/p')
+
        valid=$(echo $@ | sed -n 's/\([0-9]\{1,3\}.\)\{4\}:\([0-9]\+\)/&/p')
if [[ $valid != $@ ]]; then
+
        if [[ $valid != $@ ]]; then
>&2 echo "Invalid address"
+
            >&2 echo "Invalid address"
return 1
+
            return 1
fi
+
        fi
  
export http_proxy="http://$1/"
+
        export http_proxy="http://$1/"
export https_proxy=$http_proxy
+
        export https_proxy=$http_proxy
export ftp_proxy=$http_proxy
+
        export ftp_proxy=$http_proxy
export rsync_proxy=$http_proxy
+
        export rsync_proxy=$http_proxy
echo "Proxy environment variable set."
+
        echo "Proxy environment variable set."
return 0
+
        return 0
fi
+
    fi
  
echo -n "username: "; read username
+
    echo -n "username: "; read username
if [[ $username != "" ]]; then
+
    if [[ $username != "" ]]; then
echo -n "password: "
+
        echo -n "password: "
read -es password
+
        read -es password
local pre="$username:$password@"
+
        local pre="$username:$password@"
fi
+
    fi
  
echo -n "server: "; read server
+
    echo -n "server: "; read server
echo -n "port: "; read port
+
    echo -n "port: "; read port
export http_proxy="http://$pre$server:$port/"
+
    export http_proxy="http://$pre$server:$port/"
 
     export https_proxy=$http_proxy
 
     export https_proxy=$http_proxy
 
     export ftp_proxy=$http_proxy
 
     export ftp_proxy=$http_proxy

Revision as of 17:03, 8 September 2014

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: please use the first argument of the template to provide a brief explanation. (Discuss in Talk:Proxy server#)

Introduction

A proxy is "an interface for a service, especially for one that is remote, resource-intensive, or otherwise difficult to use directly". Source: Proxy - Wiktionary.

Environment variables

Some programs (like wget) use environment variables of the form "protocol_proxy" to determine the proxy for a given protocol (e.g. HTTP, FTP, ...).

Below is an example on how to set these variables in a shell:

 export http_proxy=http://10.203.0.1:5187/
 export https_proxy=$http_proxy
 export ftp_proxy=$http_proxy
 export rsync_proxy=$http_proxy
 export no_proxy="localhost,127.0.0.1,localaddress,.localdomain.com"

Some programs look for the all caps version of the environment variables.

If the proxy environment variables are to be made available to all users and all applications, the above mentioned export commands may be added to a script, say "proxy.sh" inside /etc/profile.d/. The script has to be then made executable. This method is helpful while using a Desktop Environment like Xfce which does not provide an option for proxy configuration. For example, Chromium browser will make use of the variables set using this method while running XFCE.

Alternatively you can automate the toggling of the variables by adding a function to your .bashrc (thanks to Alan Pope for original script idea)

function proxy_on() {
    export no_proxy="localhost,127.0.0.1,localaddress,.localdomain.com"

    if (( $# > 0 )); then
        valid=$(echo $@ | sed -n 's/\([0-9]\{1,3\}.\)\{4\}:\([0-9]\+\)/&/p')
        if [[ $valid != $@ ]]; then
            >&2 echo "Invalid address"
            return 1
        fi

        export http_proxy="http://$1/"
        export https_proxy=$http_proxy
        export ftp_proxy=$http_proxy
        export rsync_proxy=$http_proxy
        echo "Proxy environment variable set."
        return 0
    fi

    echo -n "username: "; read username
    if [[ $username != "" ]]; then
        echo -n "password: "
        read -es password
        local pre="$username:$password@"
    fi

    echo -n "server: "; read server
    echo -n "port: "; read port
    export http_proxy="http://$pre$server:$port/"
    export https_proxy=$http_proxy
    export ftp_proxy=$http_proxy
    export rsync_proxy=$http_proxy
}

function proxy_off(){
    unset http_proxy
    unset https_proxy
    unset ftp_proxy
    unset rsync_proxy
    echo -e "Proxy environment variable removed."
}

Omit username or password if they are not needed.

As an alternative, you may want to use the following script. Change the strings "YourUserName", "ProxyServerAddress:Port", "LocalAddress" and "LocalDomain" to match your own data, then edit your ~/.bashrc to include the edited functions. Any new bash window will have the new functions. In existing bash windows, type source ~/.bashrc. You may prefer to put function definitions in a separate file like functions then add source functions to .bashrc instead of putting everything in .bashrc. You may also want to change the name "myProxy" into something short and easy to write.

 #!/bin/bash

 assignProxy(){
   PROXY_ENV="http_proxy ftp_proxy https_proxy all_proxy HTTP_PROXY HTTPS_PROXY FTP_PROXY ALL_PROXY"
   for envar in $PROXY_ENV
   do
     export $envar=$1
   done
   for envar in "no_proxy NO_PROXY"
   do
      export $envar=$2
   done
 }

 clrProxy(){
   assignProxy "" # This is what 'unset' does.
 }

 myProxy(){
   user=YourUserName
   read -p "Password: " -s pass &&  echo -e " "
   proxy_value="http://$user:$pass@ProxyServerAddress:Port"
   no_proxy_value="localhost,127.0.0.1,LocalAddress,LocalDomain.com"
   assignProxy $proxy_value $no_proxy_value
 }
 

Keep proxy through sudo

If the proxy environment variables are set for the user only (say, from manual commands or .bashrc) they will get lost when running commands with sudo (or when programs like yaourt use sudo internally).

A way to prevent that is to add the following line to the sudo configuration file (accessible with visudo) :

Defaults env_keep += "http_proxy https_proxy ftp_proxy"

You may also add any other environment variable, like rsync_proxy, or no_proxy.

Automation with network managers

  • NetworkManager cannot change the environment variables.
  • netctl could set-up these environment variables but they would not be seen by other applications as they are not child of netctl.

About libproxy

libproxy (which is available in the extra repository) is an abstraction library which should be used by all applications that want to access a network resource. It still is in development but could lead to a unified and automated handling of proxies in GNU/Linux if widely adopted.

The role of libproxy is to read the proxy settings form different sources and make them available to applications which use the library. The interesting part with libproxy is that it offers an implementation of the Web Proxy Autodiscovery Protocol and an implementation of Proxy Auto-Config that goes with it.

The /usr/bin/proxy binary takes URL(s) as argument(s) and returns the proxy/proxies that could be used to fetch this/these network resource(s).

Note: the version 0.4.11 does not support http_proxy='wpad:' because { pkg-config 'mozjs185 >= 1.8.5'; } fails .

As of 06/04/2009 libproxy is required by libsoup. It is then indirectly used by the Midori browser.

Web Proxy Options

  • Squid is a very popular caching/optimizing proxy
  • Privoxy is an anonymizing and ad-blocking proxy
  • For a simple proxy, ssh with port forwarding can be used

Simple Proxy with SSH

Connect to a server (HOST) on which you have an account (USER) as follows

ssh -D PORT USER@HOST

For PORT, choose some number which is not an IANA registered port. This specifies that traffic on the local PORT will be forwarded to the remote HOST. ssh will act as a SOCKS server. Software supporting SOCKS proxy servers can simply be configured to connect to PORT on localhost.

Using a SOCKS proxy

There are two cases:

  • the application you want to use handles SOCKS5 proxies (for example Firefox), then you just have to configure it to use the proxy.
  • the application you want to use does not handle SOCKS proxies, then you can try to use tsocks or proxychains-ng.

In Firefox, you can use the SOCKS proxy in the menu Preferences > Network > Settings. Choose "Manual Proxy Configuration", and set the SOCKS Host (and only this one, make sure the other fields, such as HTTP Proxy or SSL Proxy are left empty). For example, if a SOCKS5 proxy is running on localhost port 8080, put "127.0.0.1" in the SOCKS Host field, "8080" in the Port field, and validate.

If using proxychains-ng, the configuration takes place in /etc/proxychains.conf. You may have to uncomment the last line (set by default to use Tor), and replace it with the parameters of the SOCKS proxy. For example, if you are using the same SOCKS5 proxy as above, you will have to replace the last line by:

socks5 127.0.0.1 8080

Then, proxychains-ng can be launched with

proxychains <program>

Where <program> can be any program already installed on your system (e.g. xterm, gnome-terminal, etc).

Proxy settings on GNOME3

Some programs like Chromium prefer to use the settings stored by gnome. These settings can be modified through the gnome-control-center front end and also through gsettings.

gsettings set org.gnome.system.proxy mode 'manual' 
gsettings set org.gnome.system.proxy.http host 'proxy.localdomain.com'
gsettings set org.gnome.system.proxy.http port 8080
gsettings set org.gnome.system.proxy.ftp host 'proxy.localdomain.com'
gsettings set org.gnome.system.proxy.ftp port 8080
gsettings set org.gnome.system.proxy.https host 'proxy.localdomain.com'
gsettings set org.gnome.system.proxy.https port 8080
gsettings set org.gnome.system.proxy ignore-hosts "['localhost', '127.0.0.0/8', '10.0.0.0/8', '192.168.0.0/16', '172.16.0.0/12' , '*.localdomain.com' ]"

This configuration can also be set to automatically execute when Network Manager connects to specific networks , by using the package proxydriverAUR from the AUR