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[Iljitsch van Beijnum]

On 28-aug-2006, at 9:58, Stig Venaas wrote:

> A common problem with tunneling is also that the two ends of the  
> tunnel are configured with different MTUs, which cause problems  
> even if PMTUD might work. I've seen this happen many times.

Actually I don't remember this being a problem in my tests because  
tunnel implementations tend to be able to receive packets that are  
larger than their MTU. I.e., when there is a tunnel between a Linux  
system (usually 1480 byte tunnel MTU) and a BSD system (usually 1280  
byte tunnel MTU) and the Linux system sends a 1480 byte packet, the  
BSD system accepts the packet.

>> There is one other option that may work to some degree in IPv6:   
>> rewriting the TCP MSS option. But I'm not aware of any gear that   
>> supports this for IPv6.

> And it is ugly, so I don't really miss it :)

(-:

Iljitsch