Hi, Does SER hold registered SIP clients' addresses? I use DHCP server to address IPaddresses to SIP clients in my small SIP network. The diagram of the topology is shown below; DHCP -----------------+ | Client A ------------+ | | | Hub | | Client B ------------+ | | SER --------------------+ In this case, I don't have a DNS server yet. I wanted to know if DNS is necessary here. Thnak you. Hiro