Hi Michael, On Fri, Jul 22, 2016 at 11:57:32PM +0100, Michael Grant wrote: > Why is it w, who, and finger truncate an ipv6 address just after the first > 4 characters of the address (the first :)?
It isn't a great answer but I'm guessing the honest one is that it's because they come from a time before IPv6 and may not have been updated in the best way since then. > % who > mgrant pts/1 2016-07-18 06:15 (2a00:S.1) I type "who" on Debian jessie and I do get the full IPv6 address: $ who andy pts/6 2016-07-23 01:42 (2001:ba8:1f1:f019::2) $ who --version who (GNU coreutils) 8.23 Copyright (C) 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by Joseph Arceneaux, David MacKenzie, and Michael Stone. > % w > 18:37:31 up 4 days, 12:26, 4 users, load average: 0.05, 0.07, 0.05 > USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT > mgrant pts/1 2a00:S.1 Mon06 4days 0.02s 0.02s /bin/bash Using the PROCPS_FROMLEN as documented in the man page, I can increase the width of the "FROM" column: $ PROCPS_FROMLEN=32 w 01:46:09 up 97 days, 10:48, 6 users, load average: 0.09, 0.08, 0.06 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT andy pts/6 2001:ba8:1f1:f019::2 01:42 0.00s 0.16s 0.00s w $ w --version w from procps-ng 3.3.9 > % finger > Login Name Tty Idle Login Time Office Office > Phone > mgrant Michael Grant pts/1 4d Jul 18 06:15 (2a00:S.1) I don't have "finger" installed, so will leave investigation of that one to someone else. > The 'last' command does a little better, it truncates at 16 characters: > > mgrant pts/0 2a00:23c4:6d10:4 Fri Jul 22 18:04:00 2016 still > logged in Using the "-a" option to put the hostname/IP at the end does allow it to be of arbitrary length: $ last -a andy pts/6 Sat Jul 23 01:42 still logged in 2001:ba8:1f1:f019::2 > > netstat does a little better still but not much: > > tcp6 0 2640 2600:3c00::ffff:9:22 2a00:23c4:6d10:4d:36663 > ESTABLISHED 12345/sshd: mgrant "--wide" works for me. $ netstat --protocol inet6 --wide Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp6 0 164 2001:ba8:1f1:f02c::2:ssh bitfolk.com:60756 ESTABLISHED > This seems so basic. Could all of these programs except tcpdump be broken > with respect to displaying ipv6 addresses? It didn't seem that hard to find this info from looking at the relevant man pages… Cheers, Andy -- http://bitfolk.com/ -- No-nonsense VPS hosting
