[dns-operations] PMTUD of .org servers
rick.jones2 at hp.com
Fri Jun 19 17:11:55 UTC 2009
> at which point EDNS will suffer badly, and TCP fallback will be used. so
> like i said, solaris just can't be a good EDNS server. interesting.
I'm guessing then that HP-UX 11i will be in the same boat.
Since I'm more than willing to demonstrate my cluelessness :) why is it
felt that the occasional drop from PMTU will cause such a degree of
suffering? Doesn't it depend on the frequency of queries relative to
the PMTU entry timeouts? (ip_ire_pathmtu_interval in HP-UX ndd-speak).
And is wiretapping the ICMP really going to help much in named
(udp_pass_up_icmp in HP-UX nddspeak)? IIRC on those hosts where DF is
set on UDP, the arrival of the ICMP message is going to cause a PMTU
route to be created and there will be suitable IP fragmentation on the
next send(s) to that destination. Unless named is going to keep a copy
of a reply on the off chance an ICMP is going to arrive it doesn't
really benefit from getting the ICMP message(s) does it?
I suppose when named is sending a request there might be value, but is
that going to be worth the overheads?
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