I switched to beta 2.45 because of the increasing amount of ICMP type 8 (echo) packet filtering/limiting on the net. The ability to configure PingPlotter to use UDP (UNIX Style) packet is good, but there is another limitation (i think). UNIX traceroute launchs UDP probe packets with a small ttl then listens for an ICMP type 11 (time exceeded) reply. I presume that's what beta 2.45 configured for "UNIX style" packet type is doing - am I right?

The problem I'm seeing (I think) is domains that are now apparently filtering ICMP type 11 packets at the edge. I'm not complain about pingplotter, just about the state of the net.

You're absolutely right.

There are definitely domains that are filtering time expired replies. Unfortunately, there's not much we can do to "get through" on these. UDP helps primarily with providers that block outbound ICMP echo requests, and these cases usually show unreachable destination very close to hop 1. There are some cases where it helps on the other (far) end of the route as well, but not nearly as often as it helps when the block is on the close end.

UDP packets add one additional "tool", but it isn't the solution for every situation, unfortunately.