Hi All,

I am experiencing an issue when i try to contact xy@cisco.com.
I found that kamailio/sip-router can't resolve by default resolving way a TCP + SRV records from domain cisco.com.

e.g. cisco.com
misi@alma:~$ host -t NAPTR cisco.com
cisco.com has no NAPTR record
misi@alma:~$ host -t SRV _sip._udp.cisco.com
Host _sip._udp.cisco.com not found: 3(NXDOMAIN)
misi@alma:~$ host -t SRV _sip._tcp.cisco.com
_sip._tcp.cisco.com has SRV record 1 0 5060 vcsgw.cisco.com.
misi@alma:~$ host -t SRV _sips._tcp.cisco.com
_sips._tcp.cisco.com has SRV record 1 0 5061 vcsgw.cisco.com.

I can't call xy@cisco.com because it does not exists an NAPTR record in domain cisco.com,
and furthermore no SRV with udp.

But it exists sip+tcp record
and also exists an secure sip SRV, so sips+tcp record!

I read rfc3263
I find kamailio dns resolver is not working as it should according RFC3263.

If no NAPTR records are found, the client constructs SRV queries for those transport protocols it supports, and does a query for each.

So kamailio should query all (udp, tcp, tls, sctp whatever) protocols.

Can anyone help/guide me to create a fix to this issue?
My plan is to create a patch to kamailio resolver, to correct and behave according RFC3263.

Any help or guidance appreciated!