[95509] in North American Network Operators' Group
ICMP unreachables, code 9,10,13
daemon@ATHENA.MIT.EDU (Christos Papadopoulos)
Wed Mar 28 18:59:07 2007
Date: Wed, 28 Mar 2007 16:57:40 -0600
From: Christos Papadopoulos <christos@CS.ColoState.EDU>
To: nanog@merit.edu
Cc: Christos Papadopoulos <christos@CS.ColoState.EDU>
Errors-To: owner-nanog@merit.edu
First, let me thank everyone who responded to my previous
question about routers prioritizing control traffic, your
comments were much appreciated.
My next question is about responses to ICMP pings (echo request),
when they return ICMP UNREACHABLE with codes 9,10 or 13.
These codes are defined as follows:
unreachable 9 Communication with Destination Network
is Administratively Prohibited
unreachable 10 Communication with Destination Host
is Administratively Prohibited
unreachable 13 Communication Administratively Prohibited
- generated if a router cannot forward a packet
due to administrative filtering
Responses with these codes seem to imply the presence of a firewall.
Is this assumption correct or are these codes meaningless?
If this a configurable parameter, how to you typically decide what
to set it to?
Thanks!
Christos Papadopoulos
Colorado State University