Hello, working on Kamailio SCSCF module, when I receive an INVITE the serving module should find the corresponding ICSCF to forward the INVITE. In order to do this it should perform a NAPTR query, followed by a DNS SRV query and a DNS A query. In our case the serving has the following behavior: 1) it CORRECTLY make NAPTR query 2) it send an SRV query to resolve ICSCF service port having invalid response 4 times. After 4 times, so 20 seconds, it sends INVITE message to ICSCF at default port 5060. SRV query contains a null name, shown as <Root> in Wireshark. Current DNS application (MyDNS) answer with a not implemented response. I expect that the serving CSCF try to resolve the ICSCF making an SRV query and an A query to discover the service port and ip address using the domain returned by NAPTR query. I have two questions: It seems that SRV query is not valid, because it's not based on SIP domain, do you think it's correct? At least, is it possible to configure s-cscf to force an INVITE to be sent always to the same interrogating? -- Flavio Battimo flavio.battimo(a)gmail.com fbattimo(a)meetecho.com skype: flaviobattimo