Brian, > So, is there any scope for a generic UDP echo process that would allow > PMTUD without ICMP messages? It's probably easier to get a port open > in firewalls for that than to reverse the trend of ICMP filtering, as > long as the echo process has adequate DoS resistance. I would hope that we could at least ping. Or, is that off the table as well? Fred fred.l.templin@boeing.com