lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Thu, 25 Aug 2011 20:50:03 -0700
From:	Corey Hickey <>
To:	Julian Anastasov <>
CC:	Linux Netdev List <>
Subject: Re: strange routing issue--packets stop getting forwarded for a live

On 2011-08-21 02:02, Julian Anastasov wrote:
>>>> 3. MTU size; 1500 on eth0 and 1406 on tun0. Bigger packets have been
>>>> transferred fine.
>>> 	Lower MTU, it can be PMTUD problem. At 04:50:24.112658
>>> I see 7801:9169 is 1420 bytes and no ICMP FRAG NEEDED is generated.
>>> May be these two regressions explain it:
>>> 	There are 2 fixes you can try or more recent kernel
>>> tree, for example 3.1-rc2 has the fixes.
>> Many thanks for your reply--it looks like you're on to something. You
>> didn't specify which interface to lower the MTU on, so I tried them each
>> in turn, and found that lowering the MTU on the client machine to 1406
>> (matching tun0 on the router) did indeed solve the problem. That makes
>> sense in retrospect.
> 	I just wanted to note the difference in MTUs
> as a possible cause that triggers the problem. And after
> your confirmation I think the new/patched kernel should work
> without playing with MTUs.

I finally got a chance to test this, and the patched kernel works fine.
Thank you!

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists