Vulnerability Development mailing list archives

Re: ICMP and BlackICE (fwd)


From: Jim Wildman <jim () ROSSBERRY COM>
Date: Fri, 8 Sep 2000 07:53:36 -0500

I've found that out as well.  For instance, aggressive icmp blocking
breaks www.four11.com.

But which ones?

--------------------------------------------------------------------------
Jim Wildman                    Managing Consultant, marchFIRST
jim () rossberry com               jim.wildman () marchfirst com
www.rossberry.com                          www.marchfirst.com
(513)766-2002 x4209            (972)560-7356

On Thu, 7 Sep 2000, James Robbins wrote:

jed,
    We just got bit by this a little while ago.  You cannot block all
ICMP traffic.  Ping is only one type of service sent over ICMP.
A list of the services supported by ICMP are:

Echo Reply (Ping)
Destination Unreachable
Source Quench
Redirect (change a route)
Echo Request (Ping)
Time Exceeded for a Datagram
Parameter Problem on a Datagram
Timestamp Request
Timestamp Reply
Information Request
Information Reply
Address Mask Request
Address Mask Reply

Some of these you can block with no ill effect.  Others will
break a lot of stuff.

--
James A. Robbins
Senior Design Engineer, Network Engineer
The Ohio State University
Chemistry Department



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