Problem with closing tcp session between cisco and freebsd

[Zherdev Anatoly]

On Tue, 16 Mar 2004 10:59:06 +0100
Andre Oppermann <andre at freebsd.org> wrote:

> Zherdev Anatoly wrote:
> > 
> > Hello.
> > 
> > I have problem with tcp session close between cisco and freebsd
> > Looks like that it bug in freebsd tcp stack.
> 
> What version of FreeBSD and Cisco IOS do you run on these machines?

OOPS. Sorry :(

FreeBSD 4.9-STABLE cvsupped March 3
Cisco IOS 12.2.19a ip only Cisco 5300



> 
> -- 
> Andre
> 
> 
> > CISCO state:
> > 
> > sh tcp brief
> > 62935208  CISCO..990    FREEBSD.513 FINWAIT1
> > 
> > FreeBSD state:
> > 
> > netstat -an
> > tcp4   57352      0  FREEBSD.513        CISCO.990       ESTABLISHED
> > 
> > TCP session from cisco side:
> > 
> > IP: s=CISCO (local), d=FREEBSD (FastEthernet0), len 41,
> > sending TCP src=990, dst=513, seq=1411875745, ack=880111139, win=3983 ACK
> > PSH FIN
> > 
> > IP: s=FREEBSD (FastEthernet0), d=CISCO (FastEthernet0), len
> > 40, rcvd 3 TCP src=513, dst=990, seq=880111139, ack=1411875745, win=0 ACK
> > 
> > IP: s=CISCO (local), d=FREEBSD (FastEthernet0), len 41,
> > sending TCP src=990, dst=513, seq=1411875745, ack=880111139, win=3983 ACK
> > PSH FIN
> > 
> > IP: s=FREEBSD (FastEthernet0), d=CISCO (FastEthernet0), len
> > 40, rcvd 3 TCP src=513, dst=990, seq=880111139, ack=1411875745, win=0 ACK
> > 
> > ....
> > 
> > TCP session from FreeBSD side:
> > 
> > 12:16:25.426584 IP CISCO.990 > FREEBSD.login: FP 1411875745:1411875746(1) ack 880111139 win 3714
> > 
> > 12:16:25.426675 IP FREEBSD.login > CISCO.990: . ack 1411875745 win 0
> > 
> > 12:16:35.121888 IP CISCO.990 > FREEBSD.login: FP 1411875745:1411875746(1) ack 880111139 win 3714
> > 
> > 12:16:35.121976 IP FREEBSD.login > CISCO.990: . ack 1411875745 win 0
> > 
> > ....
> > 
> > CISCO send ACK on FreeBSD pocket and send FIN. FreeBSD send ACK with seq w/o changes win=0 (!) and ack=cisco_seq.Cisco wait ack=cisco_seq+1 on FIN but FreeBSD box don't send this and cisco retransmit FIN.
> > 
> > --
> > Zherdev Anatoly.
> > _______________________________________________
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> > http://lists.freebsd.org/mailman/listinfo/freebsd-net
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> 
> 


-- 
Zherdev Anatoly.