parallel Internet measurement utility

 scamper is a program that is able to conduct Internet measurement
 tasks to large numbers of IPv4 and IPv6 addresses, in parallel, to
 fill a specified packets-per-second rate. Currently, it supports the
 well-known ping and traceroute techniques, as well as MDA traceroute,
 alias resolution, some parts of tbit, sting, and neighbour discovery.
 .
 scamper can do ICMP-based Path MTU discovery. scamper starts with the
 outgoing interface's MTU and discovers the location of Path MTU
 bottlenecks. scamper performs a PMTUD search when an ICMP
 fragmentation required message is not returned to establish the PMTU
 to the next point in the network, followed by a TTL limited search to
 infer where the failure appears to occur.