Good morning!

I have a situation which I am sure has an explanation. I find I can ping an
Internet address, but a traceroute to the same address fails. When I run
traceroute using ICMP instead of UDP packets, the traceroute is successful.
When traceroute fails it fails at the last hop before the destination being
searched for (worked out from the successful traceroute) which seems to
indicate the route back is a problem when using UDP.

Any help in fixing this would be appreciated. I realise I am probably
missing some basic network knowledge here, so a good text on this would also
be accepted :-) .

Thank you.
Matthew Fincham