pmtud problem

[Stephen Clark]

Eli Dart wrote:

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>Stephen Clark wrote:
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>>if the pc sends a packet of 1460 bytes with the DF bit set shouldn't the
>>freebsd 4.9 system
>>send back an icmp dest unreachable - fragmentation needed and DF bit set?
>>    
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>Are you blocking icmp with a firewall filter?
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>		--eli
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Good  question - but the answer is no. The other interesting fact is 
when I drop the mtu on
the gre to 1412 I do see the icmp messages.

>>$ sysctl -a | grep mtu
>>net.inet.tcp.path_mtu_discovery: 1
>>
>>Now if I change the mtu of the gre to 1412 everything works.
>>
>>Any insight would be appreciated.
>>
>>Thanks,
>>Steve
>>    
>>
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>- --
>Eli Dart                                         Office: (510) 486-5629
>ESnet Network Engineering Group                  Fax:    (510) 486-6712
>Lawrence Berkeley National Laboratory
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