Hey Qasim,

this might be an issue with the Diameter peer state-machine, or maybe the state is set wrongly. To debug it further, you could try to: - enable debug in the logs - e.g. would be interesting to see what this line says, if it is even triggered: https://github.com/kamailio/kamailio/blob/master/src/modules/cdp/peerstatema... - try to capture a pcap, to confirm the scenario, or the exact event sequence here.

Cheers, -Dragos

On Mon, Dec 29, 2025 at 6:42 AM Qasim Loay via sr-users < sr-users@lists.kamailio.org> wrote:

Hello Kamailio Community,

We're experiencing a *critical issue* in Kamailio where S-CSCF randomly stops sending CER to HSS in some cases after establishing TCP connections, causing complete authentication failures.

Please find the attached (IMS containers + HSS )logs and the current configuration.

*Environment*

• *Kamailio Version:* kamailio 6.0.2 (x86_64/linux) d4dc5d
• *Deployment:* SCSCF and HSS as a container on same physical machine

using macvlan networking

*Components:*

• SCSCF: 172.22.1.20
• HSS: 172.22.1.3
• ICSCF: 172.22.1.19

*Problem Description*

*The issue occurs randomly* - the system works normally for periods of time, then suddenly the Diameter connection between SCSCF and HSS fails and enters a reconnection seems loop.

*Here's the cycle we're observing:*

*1. *SCSCF: WARNING: cdp [peermanager.c:337]: peer_timer(): Inactivity on peer [hss.epc.mnc092.mcc418.3gppnetwork.org] and no DWA, Closing peer...

*2. State Timeout (~40 seconds later):* S-CSCF: ERROR: cdp [peerstatemachine.c:164]: sm_process(): in state Closed timeout event Timeout

*3. Reconnection Attempt (~30 seconds later):*

SCSCF: INFO: cdp [peerstatemachine.c:551]: I_Snd_Conn_Req(): Peer hss.epc.mnc092.mcc418.3gppnetwork.org

SCSCF: INFO: cdp [receiver.c:991]: peer_connect(): Trying to connect to 172.22.1.3 port 3870

SCSCF: INFO: cdp [receiver.c:1090]: peer_connect(): Peer hss.epc.mnc092.mcc418.3gppnetwork.org:3870 connected

*4. HSS Side (waiting indefinitely):*HSS: [hss:0.19.37] 2025/12/25 04:46:39.060208 [INF] [scscf>hss:0][waiting for CER from 172.22.1.20:33284]

*Cascading Effects:*

*ICSCF accumulates branches:*

ICSCF: ERROR: tm [t_fwd.c:792]: add_uac(): maximum number of branches exceeded

ICSCF: ERROR: tm [t_fwd.c:1771]: t_forward_nonack(): failure to add branches

*Result:* each UE cannot be able to register to IMS and VoLTE service outage for all UEs

Best regards,

Qasim Loay __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!