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IP-MONITOR(8)                                           Linux                                           IP-MONITOR(8)



NAME
       ip-monitor, rtmon - state monitoring

SYNOPSIS
       ip monitor [ all | OBJECT-LIST ] [ file FILENAME ] [ all-nsid ]



OPTIONS
       -t, -timestamp
              Prints timestamp before the event message on the separated line in format:
                  Timestamp: <Day> <Month> <DD> <hh:mm:ss> <YYYY> <usecs> usec
                  <EVENT>


       -ts, -tshort
              Prints short timestamp before the event message on the same line in format:
                  [<YYYY>-<MM>-<DD>T<hh:mm:ss>.<ms>] <EVENT>


DESCRIPTION
       The ip utility can monitor the state of devices, addresses and routes continuously. This option has a slightly
       different format.  Namely, the monitor command is the first in the command line and then the object list fol‐
       lows:

       ip monitor [ all | OBJECT-LIST ] [ file FILENAME ] [ all-nsid ]

       OBJECT-LIST is the list of object types that we want to monitor.  It may contain link, address, route, mroute,
       prefix, neigh, netconf and nsid.  If no file argument is given, ip opens RTNETLINK, listens on it and dumps
       state changes in the format described in previous sections.


       If the all-nsid option is set, the program listens to all network namespaces that have a nsid assigned into
       the network namespace were the program is running.  A prefix is displayed to show the network namespace where
       the message originates. Example:

         [nsid 0]10.16.0.112 dev eth0 lladdr 00:04:23:df:2f:d0 REACHABLE



       If the file option is given, the program does not listen on RTNETLINK, but opens the given file, and dumps its
       contents. The file should contain RTNETLINK messages saved in binary format.  Such a file can be generated
       with the rtmon utility. This utility has a command line syntax similar to ip monitor.  Ideally, rtmon should
       be started before the first network configuration command is issued. F.e. if you insert:

               rtmon file /var/log/rtmon.log

       in a startup script, you will be able to view the full history later.


       Nevertheless, it is possible to start rtmon at any time.  It prepends the history with the state snapshot
       dumped at the moment of starting.


SEE ALSO
       ip(8)