Hello, We are facing a problem when using UDPCast in multicast mode. When I start a transfer from one pc to another, no problem. But when I start a transfer from one pc to two or more pc's, new booted clients can't get a ip-address from the DHCP-server anymore. We have a rather complicated network, with lots of subnets. I contacted network-support and they presume it could be a conflict with the VVPR (Virtual Router Redundancy Protocol) which also uses multicast. I already played with several settings, like: udp-sender --ttl 1 and udp-receiver --ttl 1 udp-sender --ttl 2 and udp-receiver --ttl 2 udp-sender --mcast-rdv-address 224.0.0.3 and udp-receiver --mcast-rdv-address 224.0.0.3 But the problem persists. The problem only starts when the actual transfer is initiated. While udp-receiver is waiting for the clients to connect there is no problem yet, but as soon as data is being transferred (multicast), new booted clients in the network can't find the DHCP-Server, don't get an IP-addresses, can't PXE boot anymore. I hope somebody understands what is going on here, and if there is a solution. We really need udpcast in our environment. Thanks in advance for all help. Steve Dubois ICT Manager Education City of Ghent Belgium.