strange netstat -ian output

Hajimu UMEMOTO ume at freebsd.org
Thu Jan 20 15:26:22 UTC 2011


Hi,

>>>>> On Wed, 19 Jan 2011 03:44:31 +0100
>>>>> Bernd Walter <ticso at cicely7.cicely.de> said:

ticso> This is one of the blocks for this interface:
ticso> re0    1500 2a02:21e0:16e 2a02:21e0:16e0:20        0     -     -        1     -     -
ticso>                           ff02:1::2          (refs: 1)
ticso>                           ff02:1::d          (refs: 1)
ticso>                           ff02:1::202        (refs: 1)
ticso>                           ff02:1::1:ff00:103 (refs: 1)
ticso>                           ff01:1::1          (refs: 1)
ticso>                           ff02:1::2:6214:d648(refs: 1)
ticso>                           ff02:1::1          (refs: 1)
ticso>                           ff02:1::1:ff00:7992(refs: 1)

ticso> 2a02:21e0:16e seems to be the truncated IP.
ticso> The first line has 2a02:21e0:16e0:20 - I assume this should say 2a02:21e0:16e0:2000::103,
ticso> but it is truncated as well...

Yes, an IPv6 address is too long for the traditional netstat output
format. :)

ticso> Adding -W won't help on truncation.

It seems -W is not handled, here.

ticso> - ff02:1::2
ticso>   is not just truncated - this obviously should be ff02::2.
ticso>   This '1' is part of every multicst address listed, although they
ticso>   don't belong there.
ticso>   By looking at systems with a large number of interfaces I came to the
ticso>   conclusion that this is the scope ID, but why is it listed as part
ticso>   of the IP?

Yes, it is the internal scope address representation of the KAME IPv6
stack.  It is hided in the output of 'netstat -rn'.  But, it seems not
for `netstat -ani'.  There is no reason to not hide it for `netstat
-ani', IMHO.  So, I've just committed to hide it:

	http://svn.freebsd.org/viewvc/base?view=revision&revision=217642

Sincerely,

--
Hajimu UMEMOTO @ Internet Mutual Aid Society Yokohama, Japan
ume at mahoroba.org  ume@{,jp.}FreeBSD.org
http://www.imasy.org/~ume/


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