Date: Tue, 19 Jul 2005 17:18:38 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: gnn@freebsd.org Cc: freebsd-net@freebsd.org, Jeremie Le Hen <jeremie@le-hen.org> Subject: Re: Problem with Path MTU Discovery Message-ID: <20050719151838.GL39292@obiwan.tataz.chchile.org> In-Reply-To: <m2mzoqt5h8.wl%gnn@neville-neil.com> References: <20050713130042.GV39292@obiwan.tataz.chchile.org> <m2mzoqt5h8.wl%gnn@neville-neil.com>
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Hi George,
sorry for the delay.
> > I set a gif(4)-based IPSec tunnel between my network and a friend's one.
> > This works pretty well, except that Path MTU Discovery doesn't work.
> >
> > Quick draw:
> > MTU: 1500 MTU:1280 MTU:1500
> > Comp1 --------- Gate1 -------- Gate2 -----+-- Comp2
> > RELENG_5 RELENG_4 RELENG_5 | RELENG_5
> > |
> > +-- Comp3
> > RELENG_5
>
> Can you look at the routing table for each of Comp1 and Comp2 and also
> use the -W flag to show the path MTU? If there is something wonky in
> the routing table then TCP will not hear about the MTU change.
There doesn't seem to be strange MTUs in routing table (each host has
multiple jails, which explains why the routing table is somewhat large).
%%%
comp1:root# netstat -rnWf inet
Routing tables
Internet:
Destination Gateway Flags Refs Use Mtu Netif Expire
default 192.168.1.1 UGS 0 3878073 1500 em0
127.0.0.1 127.0.0.1 UH 0 4 16384 lo0
192.168.1 link#3 UC 0 0 1500 em0
192.168.1.1 00:09:5b:1a:48:94 UHLW 1 594449 1500 em0 1169
192.168.1.25 00:04:23:89:e5:84 UHLW 0 20232 1500 lo0 =>
192.168.1.25/32 link#3 UC 0 0 1500 em0
192.168.1.53 00:04:23:89:e5:84 UHLW 0 24765 1500 lo0 =>
192.168.1.53/32 link#3 UC 0 0 1500 em0
192.168.1.178 00:c0:9f:94:39:8f UHLW 0 275 1500 em0 316
192.168.1.241/32 link#3 UC 0 0 1500 em0
comp2:root# netstat -rnWf inet
Routing tables
Internet:
Destination Gateway Flags Refs Use Mtu Netif Expire
default 192.168.4.13 UGS 0 58623 1500 xl0
127.0.0.1 127.0.0.1 UH 0 1244 16384 lo0
192.168.4 link#1 UC 0 0 1500 xl0
192.168.4.4 00:60:08:60:fe:10 UHLW 0 20 1500 lo0
192.168.4.13 00:0a:5e:3d:40:cb UHLW 1 1307764 1500 xl0 1012
192.168.4.40 00:60:08:60:fe:10 UHLW 0 1255 1500 lo0 =>
192.168.4.40/32 link#1 UC 0 0 1500 xl0
192.168.4.49 00:60:08:60:fe:10 UHLW 0 2317 1500 lo0 =>
192.168.4.49/32 link#1 UC 0 0 1500 xl0
192.168.4.50 00:60:08:60:fe:10 UHLW 0 1220 1500 lo0 =>
192.168.4.50/32 link#1 UC 0 0 1500 xl0
192.168.4.51 00:60:08:60:fe:10 UHLW 0 4763999 1500 lo0 =>
192.168.4.51/32 link#1 UC 0 0 1500 xl0
192.168.4.52 00:60:08:60:fe:10 UHLW 0 1215 1500 lo0 =>
192.168.4.52/32 link#1 UC 0 0 1500 xl0
192.168.4.53 00:60:08:60:fe:10 UHLW 0 14393 1500 lo0 =>
192.168.4.53/32 link#1 UC 0 0 1500 xl0
192.168.4.54/32 link#1 UC 0 0 1500 xl0
192.168.4.80 00:60:08:60:fe:10 UHLW 0 24577 1500 lo0 =>
192.168.4.80/32 link#1 UC 0 0 1500 xl0
%%%
Thank you.
Regards,
--
Jeremie Le Hen
hen dot org >< ttz at chchile dot org >
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