MRTG-IPV6(1)                   mrtg                  MRTG-IPV6(1)



NAME
       mrtg-ipv6 - IPv6 support in MRTG

OVERVIEW
       MRTG and cfgmaker support SNMP over IPv6. IPv6 targets can
       be specified by hostname or IPv6 address, and if the
       required libraries are present (see below), queries will
       use IPv6.

USAGE
       Enabling IPv6

       IPv6 is currently disabled by default and must be explic-
       itly enabled. In MRTG this is done by turning on the
       EnableIPv6 global option in the configuration file. In
       cfgmaker, it is enabled with the --enable-ipv6 command-
       line option.

       If IPv6 is disabled, MRTG and cfgmaker should behave in
       exactly the same way as previous versions. So the addition
       of IPv6 support should have no effect on existing MRTG
       setups unless IPv6 is enabled.

       IPv6 support requires the Socket6 and INET6 libraries (see
       below). If MRTG can't find them, IPv6 is disabled.

       Specifying IPv6 targets

       IPv6 targets may be specified by name or IPv6 address.
       Numeric IPv6 addresses may be used with both cfgmaker and
       MRTG, but they must be enclosed in square brackets.

       For example, a target could be specified as:

        public@[2001:760:4::]:161

       Hostnames work as expected: first an IPv6 name lookup is
       tried, then an IPv4 lookup.

       Targets that do not support SNMP over IPv6

       Many targets (this currently includes all Cisco routers)
       do not yet support SNMP over IPv6 and must be monitored
       over IPv4. This can cause problems if you specify a target
       through its DNS name and the name maps to both the IPv6
       address and the IPv4 address of the target: MRTG will only
       try IPv6, and will fail.

       To query these targets, use the IPv4Only per-target
       option, which tells MRTG not to use SNMP over IPv6 for the
       target.

       MRTG does not fall back to IPv4 for performance and cor-
       rectness reasons. If there are many routers to query, a
       timeout for every router would make MRTG take too long to
       query them all. And if, for some reason, IPv6 connectivity
       to the target is lost, MRTG's error messages can help fig-
       ure out what is wrong.

       cfgmaker does fall back from IPv6 to IPv4. If IPv6 is
       enabled and cfgmaker is given a hostname that resolves to
       both an IPv6 and an IPv4 address, it first tries to query
       the target over IPv6. If it receives no answer, it tries
       again using IPv4. If the target answers, cfgmaker sets the
       IPv4Only option in the generated config file.

IPv6 LIBRARIES
       Libraries required

       IPv6 support requires the Socket6 and INET6 Perl modules.
       Both can be downloaded from CPAN:

       http://search.cpan.org/author/UMEMOTO/Socket6/

       http://search.cpan.org/author/MONDEJAR/INET6/

       If you use Debian, you will need the packages lib-
       socket6-perl and libio-socket-inet6-perl, which are (or
       should soon be) in unstable.

       So far, IPv6 support has been tested on Linux only, and
       only with Socket6 version 0.12. Also note that IPv6 won't
       work at all if you don't have INET6.pm version 2.00 or
       newer.

       Installing the libraries

       Building and installing Socket6 and INET6 is very simple.
       For each module, just unpack the archive and then do:

        perl Makefile.PL
        make

       and then:

        su
        make install

       If you have installed the libraries successfully, cfgmaker
       and mrtg should automatically detect them and allow IPv6
       support to be enabled.



2.10.13                     2004-01-19               MRTG-IPV6(1)
