Hello,

Using Kamailio 4.1.

I’m having some problems with the Max-Forwards header being decremented by almost 50 when Kamailio relays the INVITE to the next hop.

The INVITE is received by Kamailio with the value of 65, but when sent to the next hop it has the value of 16.

I’m not altering the max-forwards header value in any way in the config script. At least not explicitly.

Are there any known constructs which indirectly affect the Max-Forwards header?

10.0.0.16 is the Kamailio server.

U 10.0.0.10:5060 -> 10.0.0.16:5060

INVITE sip:3110123456@10.0.0.16:5060 SIP/2.0.

Via: SIP/2.0/UDP 10.0.0.10;rport;branch=z9hG4bKeg5g6U4Dc5HeS.

Max-Forwards: 65.

From: "31765123456" <sip:31765123456@10.0.0.10>;tag=9Z7avj87Bc2gm.

To: <sip:3110123456@10.0.0.16:5060>.

Call-ID: e089c971-f3a8-1231-c2bb-000c2941b070.

CSeq: 54291565 INVITE.

Contact: <sip:mod_sofia@10.0.0.10:5060>.

User-Agent: CM Carrier SBC.

Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, NOTIFY.

Supported: timer, precondition, path, replaces.

Allow-Events: talk, hold, conference, refer.

Content-Type: application/sdp.

Content-Disposition: session.

Content-Length: 205.

U 10.0.0.16:5060 -> 10.0.0.31:5060

INVITE sip:3110123456@10.0.0.25:5060 SIP/2.0.

Record-Route: <sip:10.0.0.16;lr=on>.

Via: SIP/2.0/UDP 10.0.0.16;branch=z9hG4bKe501.5459c149e5fa2c6c723149661017aa3d.0.

Via: SIP/2.0/UDP 10.0.0.10;rport=5060;branch=z9hG4bKeg5g6U4Dc5HeS.

Max-Forwards: 16.