netdev - PROBLEM: Fragmentation issue with 1521 bytes ip packets

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Message-ID: <CAPFXtPexGpVyGGuKdjpuH+cxOaxa7KeBfmFrs39=NW7LsZ6-bw@mail.gmail.com>
Date:	Tue, 15 May 2012 10:00:52 -0400
From:	Omar Alhassane <oalhassane@...il.com>
To:	netdev@...r.kernel.org
Subject: PROBLEM: Fragmentation issue with 1521 bytes ip packets

Hello Folks,

I think i may have found a problem with the linux networking stack.
Below is a description of the problem.

[1.] One line summary of the problem:
No response to pings of certain sizes.

[2.] Full description of the problem/report:
Using hping3, when i ping a linux machine with 1521 bytes ip packets i
get only one response.
But when i use 1482 bytes, everything works fine. I've tried this with
both tcp and udp. The MTU of my interface is 1500.
[3.] Keywords (i.e., modules, networking, kernel):
ip, udp, tcp, networking, fragmentation
[4.] Kernel version (from /proc/version):
3.3.1
[5.] Output of Oops.. message (if applicable) with symbolic information
[6.] A small shell script or example program which triggers the
problem (if possible)
The following commands works only if the target has tcp port 22 open

hping3 -d 1481 -S -P 22 10.0.30.225 (only one response)
hping3 -d 1482 -S -P 22 10.0.30.225 (works fine)

Can somebody confirm if this is a problem?

Thanks
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