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From: "Niccolò Belli" <darkbasic@linuxsystems.it>
To: netfilter@vger.kernel.org
Cc: wireshark-users@wireshark.org, lartc@lists.linuxsystems.it
Subject: Re: Problem with ip spoofing load balancing
Date: Wed, 26 Oct 2011 22:38:55 +0200	[thread overview]
Message-ID: <4EA86FDF.8090906@linuxsystems.it> (raw)
In-Reply-To: <alpine.LFD.2.00.1110262235340.1558@ja.ssi.bg>

Il 26/10/2011 21:43, Julian Anastasov ha scritto:
> 	I looked at broken-spoofing-server.pcap and
> broken-spoofing-client.pcap
>
> 	It looks like that this packet comes after some
> packet that is dropped before server:
>
> IP 2.119.245.36.80>  88.38.77.130.39243: Flags [P.], seq 1449:1534, ack 602, win 438, options [nop,nop,TS val 17124611 ecr 56937089], length 85
>
> 	May be the seq 1:1449 packet can not reach 2.119.245.36.80,
> that is why it does not go to client 88.38.77.130.39243.
> May be server is a virtual server or something like that.
>
> 	I guess someone before 2.119.245.36.80 is sending
> large packets and some MTU is low and may be due to missing
> ICMP the sender there can not learn the lower path MTU.
> May be client can use ip route add ... advmss 1400 to check
> if problem is fixed that way. May be there is some tunnel
> behind the server that uses lower MTU.
>
> 	Note that some 3.0.X kernels have problem that
> ICMP is not sent and this can cause PMTU problems.

SOLVED! Thanks Julian Anastasov.

Niccolò

       reply	other threads:[~2011-10-26 20:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4EA821DD.1050306@linuxsystems.it>
     [not found] ` <alpine.LFD.2.00.1110262235340.1558@ja.ssi.bg>
2011-10-26 20:38   ` Niccolò Belli [this message]
2011-10-25 22:10 Problem with ip spoofing load balancing Niccolò Belli

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