[Serusers] Residential Gateways

Running Redhat V9 and have installed the SIP Express Router (ser) packages. Have two Allied Telesyn Residential Gateways (192.168.20.2 and 192.168.20.3) and laptop (192.168.20.4) running ser connecting to a managed switch IP address (192.168.20.1 (gateway)) The RG's are configured to access the Proxy server, & Domain server at 192.168.20.4 and the Gateway as 192.168.20.1 The Domain is called ati.com. When connected all together I get a dial tone on the phones, however when I dial the # configured on the RG's I do not get a ring and they do not register with the ser server. When I type in the "ser start" command I see the alias entries as "127.0.0.1 localhost localdomain localhost" and "192.168.20.4 localhost.ati.com localhost" The entries in the ser.cfg relating to the localdomain have been changed to ati.com I have added the 192.168.20.4 to the hosts.cfg relating to the ati.com domain. Any idea as to why this configuration is not working. This is a lab situation with no outside connections. Thank you.