Date: Fri, 18 Jan 2002 00:51:07 -0800 From: "Crist J . Clark" <cjc@FreeBSD.ORG> To: "Reto Trachsel (NetModule)" <reto.trachsel@netmodule.com> Cc: "'net@freebsd.org'" <net@FreeBSD.ORG> Subject: Re: ICMP Redirect Message-ID: <20020118005107.E40472@blossom.cjclark.org> In-Reply-To: <F58DFF990DB0D411841D000102A7CD70090C01@tigris.pacific>; from reto.trachsel@netmodule.com on Thu, Jan 17, 2002 at 12:03:02PM %2B0100 References: <F58DFF990DB0D411841D000102A7CD70090C01@tigris.pacific>
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On Thu, Jan 17, 2002 at 12:03:02PM +0100, Reto Trachsel (NetModule) wrote:
> Hi Crist
>
> Here the Logs and outputs for you
>
> Regards
> Reto
>
> # tcpdump -vvXs 1500 'icmp'
>
> 172.16.224.24 -> BSD Host
> 172.16.1.254 -> BSD Router
>
> 12:00:43.658869 172.16.1.254 > 172.16.224.24: icmp: redirect 172.24.0.2 to
> host
> 172.16.1.252 for 172.16.224.24 > 172.24.0.2: icmp: echo request (ttl 64, id
> 2963
> 2, len 84) (ttl 64, id 12073, len 56)
Ouch. Severe line-wrap damage.
> 0x0000 4500 0038 2f29 0000 4001 1165 ac10 01fe E..8/)..@..e....
> 0x0010 ac10 e018 0501 f014 ac10 01fc 4500 0054 ............E..T
> 0x0020 73c0 0000 4001 cea5 ac10 e018 ac18 0002 s...@...........
> 0x0030 0800 8337 bba5 1600 ...7....
> 12:00:44.668972 172.16.224.24 > 172.24.0.2: icmp: echo request (ttl 64, id
> 29634
> , len 84)
> 0x0000 4500 0054 73c2 0000 4001 cea3 ac10 e018 E..Ts...@.......
> 0x0010 ac18 0002 0800 5f10 bba5 1700 4bae 463c ......_.....K.F<
> 0x0020 475c 0200 0809 0a0b 0c0d 0e0f 1011 1213 G\..............
> 0x0030 1415 1617 1819 1a1b 1c1d 1e1f 2021 2223 .............!"#
> 0x0040 2425 2627 2829 2a2b 2c2d 2e2f 3031 3233 $%&'()*+,-./0123
> 0x0050 3435 3637 4567
> 12:00:44.669009 172.16.224.24 > 172.24.0.2: icmp: echo request (ttl 63, id
> 29634
> , len 84)
> 0x0000 4500 0054 73c2 0000 3f01 cfa3 ac10 e018 E..Ts...?.......
> 0x0010 ac18 0002 0800 5f10 bba5 1700 4bae 463c ......_.....K.F<
> 0x0020 475c 0200 0809 0a0b 0c0d 0e0f 1011 1213 G\..............
> 0x0030 1415 1617 1819 1a1b 1c1d 1e1f 2021 2223 .............!"#
> 0x0040 2425 2627 2829 2a2b 2c2d 2e2f 3031 3233 $%&'()*+,-./0123
> 0x0050 3435 3637 4567
> 12:00:44.669034 172.16.1.254 > 172.16.224.24: icmp: redirect 172.24.0.2 to
> host
> 172.16.1.252 for 172.16.224.24 > 172.24.0.2: icmp: echo request (ttl 64, id
> 2963
> 4, len 84) (ttl 64, id 12154, len 56)
> 0x0000 4500 0038 2f7a 0000 4001 1114 ac10 01fe E..8/z..@.......
> 0x0010 ac10 e018 0501 133c ac10 01fc 4500 0054 .......<....E..T
> 0x0020 73c2 0000 4001 cea3 ac10 e018 ac18 0002 s...@...........
> 0x0030 0800 5f10 bba5 1700 .._.....
> $ netstat -rn
I was interested in the routing table on BSDHost, not the
router. However...
> $ ifconfig
>
> fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> inet 172.16.1.12 netmask 0xffff0000 broadcast 172.16.255.255
> inet 172.16.1.11 netmask 0xffff0000 broadcast 172.16.255.255
> inet 172.16.1.254 netmask 0xffff0000 broadcast 172.16.255.255
> inet 172.16.1.10 netmask 0xffff0000 broadcast 172.16.255.255
This is a misconfiguration. Only one of those addresses should have a
0xffff0000 netmask and the rest should be 0xffffffff. But I was
interested in BSDHost.
--
Crist J. Clark | cjclark@alum.mit.edu
| cjclark@jhu.edu
http://people.freebsd.org/~cjc/ | cjc@freebsd.org
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