nanog mailing list archives

Re: rfc1918 ignorant


From: "Petri Helenius" <pete () he iki fi>
Date: Wed, 23 Jul 2003 21:19:14 +0300





Unless of course I block ICMP for the purposes of denying traceroute but
still allow DF/etc.  Then it's not "broken" as you say.

Sure, but people "blocking all ICMP" haven´t usually heard that there are different
types and codes in ICMP.

It´s surprising how many large www sites do not work if your MTU is less
than 1500. Even if you do PMTU. (because the packets vanish somewhere
before or at the server).

Pete



-- 
David Temkin

On Wed, 23 Jul 2003, Kevin Oberman wrote:

Date: Wed, 23 Jul 2003 13:50:05 -0400 (EDT)
From: Dave Temkin <dave () ordinaryworld com>
Sender: owner-nanog () merit edu


Needs is a tough call.  Plenty of networks block ICMP at the border and
could very well be using 1918 addressing in between and you'd have no
idea.

And the network is broken.

People persist in blocking ICMP and then complain when things don't
work right. Even if you explain why blocking ICMP is breaking
something, they say "ICMP is evil and we have to block it". OK. they
are broken and when things don't work, they need to tell their
customers that they are choosing to run a network that does not work
correctly. (Not that I expect anyone to do this.)

I don't see anything "tough" about this call.




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