Making ICMP the default traceroute protocol?

[Marian Durkovic]

> I disagree.  Firstly, IWFs tend to also block ICMP.  Secondly, routers 
> sometimes queue ICMP differently than UDP (not just in their own 
> processing, which they almost always do, but also in their forwarding), 
> giving even more distortion to these data than they naturally possess 
> otherwise.

Well, that's true, however, the backward packets of traceroute probes
are ICMP "ttl exceeded" anyway...

The main motivation I'm proposing this is significantly less support for
UDP traceroutes that ICMP traceroutes. Several important www sites have
dropped UDP traceroute support (try e.g. www.cisco.com, www.google.com,
www.dtag.de or many many others). Also on intranet level, WinXP boxes
with SP2 installed have no support for UDP traceroutes either.

> If you are finding that your destinations tend to need ICMP, I'd 
> recommend aliasing traceroute to "traceroute -I".

Of course I have "traceroute -P icmp" in my alias list for some time, 
which fixes the problem for me, however I just think it's better to
have it as default and use UDP/TCP just for experienced users which
exactly know what they're doing...


	With kind regards,

		M. 

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----   Marian Durkovic                       network  manager         ----
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----   Slovak Technical University           Tel: +421 2 524 51 301   ----
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----   812 43 Bratislava, Slovak Republic    E-mail/sip: md at bts.sk    ----
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