RE: Digital Island sponsors DoS attempt?

From: Bob K (no email)
Date: Fri Oct 26 2001 - 14:44:46 EDT


On Fri, 26 Oct 2001, Quibell, Marc wrote:

> Finally, I do not believe PMTU uses pings to discover the PMTU. I believe it
> uses TCP or UDP packets at the layers above IP, and it DOES use "ICMP Packet
> Too big" responses (from the receiver) to cut it's packet size. So in
> reality, a router blocking ICMP from being routed through can still send
> these ICMP messages PMTU needs. Is this how you understand it?

Don't forget that routers or hosts beyond (from the point of view of the
host attempting PMTU) your ICMP-blocking router may have smaller MTUs than
the norm and may be trying to send ICMP errors back...

-- 
Bob <> | We're all wrong.







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