RTMON(8)                   System Manager's Manual                  RTMON(8)

NAME         top

       rtmon - listens to and monitors RTnetlink

SYNOPSIS         top

       rtmon [ options ] file FILE [ all | LISTofOBJECTS ]

DESCRIPTION         top

       This manual page documents briefly the rtmon command.

       rtmon listens on netlink socket and monitors routing table changes.

       rtmon can be started before the first network configuration command
       is issued.  For example if you insert:

       rtmon file /var/log/rtmon.log

       in a startup script, you will be able to view the full history later.
       Certainly, it is possible to start rtmon at any time. It prepends the
       history with the state snapshot dumped at the moment of starting.

OPTIONS         top

       rtmon supports the following options:

              Print version and exit.

       help   Show summary of options.

       file FILE [ all | LISTofOBJECTS ]
              Log output to FILE. LISTofOBJECTS is the list of object types
              that we want to monitor. It may contain 'link', 'address',
              'route' and 'all'. 'link' specifies the network device,
              'address' the protocol (IP or IPv6) address on a device,
              'route' the routing table entry and 'all' does what the name

       -family [ inet | inet6 | link | help ]
              Specify protocol family. 'inet' is IPv4, 'inet6' is IPv6,
              'link' means that no networking protocol is involved and
              'help' prints usage information.

       -4     Use IPv4. Shortcut for -family inet.

       -6     Use IPv6. Shortcut for -family inet6.

       -0     Use a special family identifier meaning that no networking
              protocol is involved. Shortcut for -family link.

USAGE EXAMPLES         top

       # rtmon file /var/log/rtmon.log
              Log to file /var/log/rtmon.log, then run:

       # ip monitor file /var/log/rtmon.log
              to display logged output from file.

SEE ALSO         top


AUTHOR         top

       rtmon was written by Alexey Kuznetsov <>.

       This manual page was written by Michael Prokop <>, for
       the Debian project (but may be used by others).

COLOPHON         top

       This page is part of the iproute2 (utilities for controlling TCP/IP
       networking and traffic) project.  Information about the project can
       be found at 
       If you have a bug report for this manual page, send it to,  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on
       2020-02-08.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-01-29.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to