On Wed, Jul 28, 2004 at 02:07:45PM +0100, Andrew Young wrote:
  Dear all

  For the last few years, I have set my students an assignment to use
  ping/traceroute to look at routes and performance to various places on the
  Internet, draw annotated maps, and reach various conclusions. They have
  always found it very interesting.

  For the last year I have been fighting with various packet filters that
  have been stopping me doing this. I have now reached an impasse and can't
  get traceroute to work at all (I have tried ICMP, UDP or TCP based

  As ping still works, it seems to me that my University (or their ISP) are
  filtering the "TTL Exceeded" reply. I am trying to get them to remove this,
  but I need a fallback position in case they won't.

  Does anyone have any ideas for other equivalent things I can do that aren't
  so susceptible to firewall interference.


you could take advantage of caida's years of government research
funded IP topology data:

which is available to non-commercial researchers at no cost,
and which also teaches students an immense amount about dealing
with incredibly large Internet data sets (lots of analysis
tools and packages linked from that page), which they'll
need to learn anyway if they want to do useful work in the area.