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Re: [Phys-l] Missing universities



Jason Alferness wrote:
Umm... no, not this time, but have used it before... worked fine then...

So trying it... it traced just fine... showed hops, RTT's, and whatnot... It'd certainly show if it was getting plugged at your campus borders or something... Isn't that what you're implying they might see... or else what specifically are you expecting to see? Am I missing something?

Here's from my windows box:
------------
Tracing route to carnot.physics.buffalo.edu [128.205.17.137]
over a maximum of 30 hops:

OK, now try it on something that doesn't respond to ICMP ECHO
packets, such as:

www.kutztown.edu
www.esu.edu
www.bloomu.edu
www.cup.edu
www.lhup.edu
www.wcupa.edu

I recommended tcptraceroute for a reason.

ICMP is IP protocol 1
TCP is IP protocol 6
UDP is IP protocol 17

If you think hosts (and firewalls!) treat ICMP exactly the same as TCP,
you're going to be very disappointed.

OK, the Linux trace gives more meaningless digits of precision for RTT's,

Linux isn't the issue. I didn't mention Linux. Precision isn't
the issue either. The issue is TCP versus ICMP. You can install
tcptraceroute tools for microsoft boxen ... but the microsoft
built-in tracert is ICMP only -- unless there has been a major
upgrade while I wasn't looking.

The linux version also has more options for type of service, ports...

Ports? Ports??? Unless I am greatly mistaken, ICMP doesn't even have ports.
http://www.ietf.org/rfc/rfc792.txt
That's one of the basic facts underlying the point I've been making.

blah, blah... but do I need them for this and if so for what? I can think of scenarios that it would be nice to know more, but usually problems are more simple than I first think they may be.

Yeah, but sometimes they're not ultra-simple. I'm not suggesting this is
rocket surgery ... but it doesn't have to be rocket surgery to be beyond
the reach of the microsoft built-in tracert.

I recommended tcptraceroute for a reason. Many web servers (and the associated
firewalls) are narrowly tuned to accept TCP to port 80 plus a few related things
... and not much else.