You can see ``` REGISTER sip:voip.domain.com SIP/2.0. Via: SIP/2.0/UDP 32.1.128.4:45417;rport;branch=z9hG4bKPjZ5fpsipsncRX35bosd-juQhhswwf2n.t. Max-Forwards: 70. From: sip:83@voip.domain.com;tag=zMJ4EsFF8lnLBuDCWxk52XJgy84zU180. To: sip:83@voip.domain.com. Call-ID: qlKuZzPgK8dIzwwwpRRsP8yNr3xpWzzE. CSeq: 54489 REGISTER. User-Agent: ABTO VoIP SDK. ```
These messages send not by `Kamailio`. This message send by "ABTO VoIP SDK".
You need to check "ABTO VoIP SDK" provider to config manage difference with IPv6/IPv4 address when used TCP/UDP transport.