Dont fragment and More fragments set

[Clayton Nobbs]

Testing my hpux 11.00 software on 11.11 the 11.11 box is sending out packets with both the don't fragment and more fragments bits set.

This software measures the MTU and validates that the reported MTU is correct. To do this DF must be respected or sizes that should elicit a fragmentation required message will slip through. I believe it is caused by ip_pmtu_strategy 1 as the packets are fragmented to the reported mtu after the first packet.

I have tried setting ip_pmtu_strategy to 0 but with this setting DF is cleared. The program sends raw IP icmp/udp packets with DF set in the raw IP header.

Is there some configuration setting or patch I can use to make hpux11.11 respect the DF bit?

Thanks