Re: ICMP ACL parameters

On 24/01/2013 07:03, ccie99999 wrote:
> first of all is it clear to you how traceroute works?
>
> http://en.wikipedia.org/wiki/Traceroute
>
> On Unix-like <http://en.wikipedia.org/wiki/Unix-like> operating systems,
> the traceroute utility by default uses User Datagram
> Protocol<http://en.wikipedia.org/wiki/User_Datagram_Protocol>
> (UDP) datagrams <http://en.wikipedia.org/wiki/Datagram> with destination port
> numbers <http://en.wikipedia.org/wiki/Port_number> from 33434 to 33534. The
> traceroute utility usually has an option to specify use of ICMP echo
> request (type 8) instead, as used by the
> Windows<http://en.wikipedia.org/wiki/Windows>
> *tracert* utility.
>
> does this answer to your question?

     No, it doesn't. Because that particular parameter doesn't refer to
anything above.

     That particular type of ICMP packet (ICMP traceroute - type 30)
isn't really used by any of them. Instead, you'll only see it in very...
unusual scenarios (such as an extended ping with "Record route" set).
See Scott Morris's answer (linked a bit earlier by Joe -
http://forums.internetworkexpert.com/forums/p/3081/9985.aspx ) for more
details.

     And if you need more, you can always go directly to the source:
http://tools.ietf.org/html/rfc1393#section-2.3

     A nice idea, too bad it never really quite caught on :)

-- 
Bogdan Sass
CCSP,LPIC-1,VCP5-DT,CCIE #22221 (RS)
Information Systems Security Professional
"Curiosity was framed - ignorance killed the cat"
Blogs and organic groups at http://www.ccie.net