scamper is a program that conducts traceroute to large numbers of IPv4
and IPv6 addresses in parallel to fill a specified packets-per-second rate.

scamper can do ICMP based Path MTU discovery. scamper starts with the
outgoing interface's MTU and discovers the location of PMTU bottlenecks.
Recent revision of scamper do a PMTU 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 the hop
where failure appears to occur.