[92922] in North American Network Operators' Group
Re: Refusing Pings on Core Routers??? A new trend?
daemon@ATHENA.MIT.EDU (Patrick W. Gilmore)
Thu Oct 19 22:24:28 2006
In-Reply-To: <6bb5f5b10610191914u5b7f8b0cu3e6cec4986e10bcd@mail.gmail.com>
Cc: "Patrick W. Gilmore" <patrick@ianai.net>
From: "Patrick W. Gilmore" <patrick@ianai.net>
Date: Thu, 19 Oct 2006 22:19:48 -0400
To: nanog@merit.edu
Errors-To: owner-nanog@merit.edu
On Oct 19, 2006, at 10:14 PM, Rubens Kuhl Jr. wrote:
>
>> template response -- I hear is "Well, you can't rely on traceroute
>> because of ICMP prioritisation". When you start to explain how
>> traceroute actually works (both ICMP-based and UDP-based (which
>> still relies on ICMP responses, of course!)), and that ICMP prio
>> should only affect the IP of which the router listens on (and not
>> hops beyond or at the dest), most NOCs fire back with another
>
> If I recall well, Cisco GSRs impose low priority and/or limits for all
> ICMP traffic flowing thru the box, not just packets to/from router
> itself, and there's not a knob to adjust that.
You don't recall well.
Although there is a knob if you want to tweak it. But there's a knob
for just about everything - it's just not tweaked by default.
--
TTFN,
patrick
