### Description As described at [RFC3605](https://datatracker.ietf.org/doc/html/rfc3605#section-2.1) ``` rtcp-attribute = "a=rtcp:" port [nettype space addrtype space connection-address] CRLF ``` So IP info is optional.

### Troubleshooting

#### Log Messages

``` Jun 7 09:55:57 sp2 lb[46796]: ERROR: DEFAULT_ROUTE nathelper [nathelper.c:1796]: nh_extract_mediaip(): no `IP[4|6]' in `a=rtcp' field Jun 7 09:55:57 sp2 lb[46796]: ERROR: DEFAULT_ROUTE nathelper [nathelper.c:1617]: replace_sdp_ip(): can't extract 'a=rtcp' IP from the SDP ```

#### SIP Traffic

``` INVITE sip:jsung2@192.168.88.194;line=8c86b7427b1107f SIP/2.0 Via: SIP/2.0/UDP 192.168.88.194;branch=z9hG4bK4f82.52fb005dac4fe078dd5593a1bebfa33b.0 From: sip:4316607564835@xxxx;tag=40FED3EF-60BDED10000D2F23-71F92700 To: sip:jsung2@xxxx CSeq: 939 INVITE Call-ID: CDqyvKE3ryYIRkecp_7cXA.. Max-Forwards: 69 Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, MESSAGE, OPTIONS, SUBSCRIBE P-Asserted-Identity: sip:4316607564835@sip.lab.com Diversion: sip:4316607564835@xxxx;privacy=off;counter=1 Supported: timer Session-Expires: 1800 Min-SE: 90 Content-Type: application/sdp Content-Length: 316 Contact: sip:btpsh-60baedf4-645b-3@192.168.88.194

v=0 o=Z 1623059728682 1 IN IP4 192.168.88.194 s=Z c=IN IP4 192.168.88.194 t=0 0 m=audio 20252 RTP/AVP 8 0 9 98 101 a=rtpmap:8 PCMA/8000 a=rtpmap:0 PCMU/8000 a=rtpmap:9 G722/8000 a=rtpmap:98 telephone-event/48000 a=fmtp:98 0-16 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=sendrecv a=rtcp:20253 ```

### Possible Solutions

fix for nathelper will follow

### Additional Information

``` version: kamailio 5.5.0 (x86_64/linux) ```