NAME

       network-test - check the network and test if everything is fine

SYNOPSIS

       network-test

DESCRIPTION

       The  network-test  program  will test your system's network configuration using basic tests and providing
       both information (INFO), warnings (WARN) and possible errors (ERR) based on the results of  these  tests.
       It will check and report on:
              * Status of the network interfaces of the system including: link status,
               IP addressing and number of transmitted packets and error rates.

              * Accessibility to configured routes to external networks,
                including the default network route, checking the routers configured
                to give access to the network

              * Proper host resolution, testing DNS resolution against a known host.

              *  Proper  network  connectivity, testing reachability of remote hosts using ICMP and simulating a
              web connections to a remote web server (the web server  used  for  the  tests  can  be  configured
              through the environment, see below)

       The program does not need special privileges to run as it does not do any system change.

       However,  the behaviour of the program when running as an unprivileged user is not the same as running as
       system administrator (i.e. root). If the program is run as system administrator it will try to  run  some
       tools that are only available to it to speed up some of the tests.

       The  program  relies  on the use of ip, netstat, ifconfig, arp and (when running as root) ethtool or mii-
       tool, to obtain information about the system's networking configuration (status of  available  interfaces
       and  configured  network  routes).  It  also  uses  ping, host and nc (netcat) to do tests of the network
       connectivity and ensure that the host can connect to the Internet.

ENVIRONMENT

       The program will, by default, check www.debian.org and its associated web server. If you want  to  use  a
       different check host you can setup the environment as follows:

       CHECK_HOST
              The name of a host to use when testing DNS resolution.

       CHECK_IP_ADRESS
              The IP address of the host defined in CHECK_HOST

       CHECK_WEB_HOST
              The web server to use for testing purposes when testing network connectivity.

       CHECK_WEB_PORT
              The web server port of server CHECK_WEB_HOST that will be used for testing.

EXIT STATUS

       The program will exit with error (1) if any of the network checks fail.

BUGS

       This  program  does  not  have  super  cow powers so it is unable to fix the errors by itself. It is also
       unable to detect if the network is failing due to a local firewall policy been in place so make sure  you
       check your system logs with dmesg (1) to detect if some of the active tests are being dropped due to your
       local firewall.

       Other known issues that might make the program not work reliable are:

              *  IPv6:  The  program  does not yet explicitly handle IPv6 only hosts, some of the tests might be
              biased towards IPv4 and might fail in IPv6 environments.

              * Proxies: The program does not check network connectivity for  hosts  that  connect  through  the
              Internet  using  a  proxy  gateway  for  services.  The program might report issues in hosts using
              proxies even when these might connect to the Internet properly through proxied services.

              * Firewall environments: some of the tests rely on direct connectivity to  external  hosts,  which
              are  tested using ICMP queries (through the use of ping. These tests might fail in hosts installed
              in networking environments with firewalls that block outbound ICMP communication.

SEE ALSO

       ip (8), netstat (8), ifconfig (8), ethtool (8), mii-tool (8), ping (8), nc (1) and host (1).

AUTHOR

       network-test was written by Javier Fernandez-Sanguino for the Debian GNU/Linux distribution.

COPYRIGHT AND LICENCE

       Copyright (C) 2005-2011 Javier Fernandez-Sanguino <jfs@debian.org>.

       This program is free software; you can redistribute it and/or modify  it  under  the  terms  of  the  GNU
       General  Public  License  as  published  by  the  Free Software Foundation; either version 2, or (at your
       option) any later version.

       On Debian systems, a copy  of  the  GNU  General  Public  License  may  be  found  in  /usr/share/common-
       licenses/GPL.

ifupdown-extra                                   August 23 2011                                  network-test(1)