[SR-Users] INFO: stun_parse_header: incomplete header of STUN message

Hello! After proxying a REGISTER from a WebRTC client to our SIP backend, the backend starts sending keepalives. Every 30 seconds I get a log entry in Kamailio saying: "INFO: stun [kam_stun.c:169]: stun_parse_header(): INFO: stun_parse_header: incomplete header of STUN message". Here's one such packet: No. Time Source Destination Protocol Length Info 1 0.000000 xxx.xxx.xxx.xxx yyy.yyy.yyy.yyy UDP 60 5060 ? 15060 Len=4 Frame 1: 60 bytes on wire (480 bits), 60 bytes captured (480 bits) Ethernet II, Src: JuniperN_4f:3f:f0 (40:a6:77:4f:3f:f0), Dst: 02:81:64:58:cf:d1 (02:81:64:58:cf:d1) Internet Protocol Version 4, Src: xxx.xxx.xxx.xxx, Dst: yyy.yyy.yyy.yyy 0100 .... = Version: 4 .... 0101 = Header Length: 20 bytes (5) Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT) Total Length: 32 Identification: 0x5bf5 (23541) Flags: 0x4000, Don't fragment Time to live: 56 Protocol: UDP (17) Header checksum: 0x2fc3 [validation disabled] [Header checksum status: Unverified] Source: xxx.xxx.xxx.xxx Destination: yyy.yyy.yyy.yyy User Datagram Protocol, Src Port: 5060, Dst Port: 15060 Source Port: 5060 Destination Port: 15060 Length: 12 Checksum: 0xfa28 [unverified] [Checksum Status: Unverified] [Stream index: 0] Data (4 bytes) 0000 00 00 00 00 .... Data: 00000000 [Length: 4] I found this in kam_stun.c: static int stun_parse_header(struct stun_msg* req, USHORT_T* error_code) { if (sizeof(req->hdr) > req->msg.buf.len) { /* the received message does not contain whole header */ LOG(L_INFO, "INFO: stun_parse_header: incomplete header of STUN message\n"); /* Any better solution? IMHO it's not possible to send error response * because the transaction ID is not available. */ return FATAL_ERROR; } ... Could someone please explain what's wrong? Med vennlig hilsen Pan B. Christensen Utvikler Phonect AS Brugata 19, PB 9156 Grønland, N-0133 Oslo, Norway E-post: pan.christensen@phonect.no<mailto:pan.christensen@phonect.no> Mobil: 41 88 88 00 [cid:image007.png@01D3A0E8.376921D0] <http://www.phonect.no/> [facebook_2]<https://www.facebook.com/phonectno> [LinkedIn_logo_initials (1)] <https://www.linkedin.com/company/44983?trk=tyah&trkInfo=clickedVertical%3Acompany%2CentityType%3AentityHistoryName%2CclickedEntityId%3Acompany_company_44983%2Cidx%3A0>