Solved: ICMP Types

vnovakov · ‎10-16-2007

Hi all,

I would like to know what is decimal equvalent for ICMP type ttl-exceeded?

Some of them I could use as:

0 - for echo-reply

8 - for echo

11 - for time-exceeded

I know that I can use syntax as:

permit icmp any any ttl-exceeded

but I would like to know what is decimal equvalent for it.

Best regards,

Vladimir

dominic.caron · ‎10-16-2007

That's type 3 code 4

dominic.caron · ‎10-16-2007

I dont think ttl-exeeded type exist.

ttl-exceeded is (TYPE 11,CODE 0)

ICMP message have a code field (8bit) that can give you further info.

Rate all useful post

dominic.caron · ‎10-16-2007

vnovakov · ‎10-16-2007

Thanks for quick answer!, Does it mean than that:

permit icmp any any ttl-exceeded

will allow only ICMP packets type 11 with code O and

permit icmp any any time-exceeded

will allow all ICMP type 11 with code 0 or 1?

Am I correct?

I have found a way how to add rules as ICMP type and code:

permit icmp any any 11

permit icmp any any 11 0

permit icmp any any 11 1

will apear as:

permit icmp any any time-exceeded

permit icmp any any ttl-exceeded

permit icmp any any reassembly-timeout

Also I'm confused with packet-to-big. By RFC 1885 it is Type 2 Code 0. But under Cisco ISO 12.4:

permit icmp any any 2 0

rule will not apear as:

permit icmp any any packet-too-big

am I wrong about packet-too-big icmp type and code that is used by Cisco?

regards,

Vladimir

dominic.caron · ‎10-16-2007

That's type 3 code 4

GillieLucent · ‎10-16-2007

Hi,

For more on ICMP types, refer below link :

Thanks,

Vijaybabu