We are attempting to set up a TLS connection to Cisco WebEx. It appears the certificates are working fine, but WebEx does not like the Contact portion of the Options ping. It is showing IP address instead of FQDN which I guess they are validating that against the certificate or the trunk configurat…

We were able to get it working by modifying the following: Add the following variable in res_pjsip.h AST_STRING_FIELD(external_fqdn) This will be configured in the tls transport section in pjsip.conf. Add the following structure in res_pjsip/config_transport.c ast_sorcery_object_field_register(…

There is no support in configuration for doing such a thing. It would require code modifications, which I believe some people have patches doing so for interfacing with Microsoft Teams - but those have never been contributed back.

Bad: [May 19 09:59:57] <--- Transmitting SIP request (467 bytes) to TLS:23.89.40.10:5062 ---> [May 19 09:59:57] OPTIONS sip:us18.sipconnect.bcld.webex.com SIP/2.0 [May 19 09:59:57] Via: SIP/2.0/TLS <Our Public Address>:5061;rport;branch=z9hG4bKPjfd58c245-cd0c-4442-960d-ba10dae556f3;alias [May 19 09…

Why are they checking the certificate against the Contact address? If anything, in the SIP, it should be the From address, although I seem to remember that the subject is actually sent at the TLS level, rather than in the SIP.

Thanks, we have some experience there. Will try to report back in a week or so when our devs get to it.

Cisco being Cisco I guess. They only “support” a handful of SBCs, but there should be no technical reason why any SBC can’t connect TLS. At least the Cisco TAC was responsive on the matter and spotted this issue fairly quickly.

I didn’t see this post while looking but is similar if not exactly what @jcolp was referring to. [image] FQDN in the contact header Asterisk SIP Im peering with a SIP system over TLS which requires to send the FQDN in the host portion of the contact header. Im using the ex…

Options Ping Contact Needs FQDN Instead of IP Address

Asterisk Asterisk SIP

ejlviking May 19, 2025, 6:23pm 7

I didn’t see this post while looking but is similar if not exactly what @jcolp was referring to.

Topic		Replies	Views
Asterisk16 PJSIP "Contact:" ( fqdn problem) Asterisk SIP	8	1946	October 25, 2018
FQDN in the contact header Asterisk SIP	5	2682	November 6, 2020
Issue with contact in pjsip Asterisk SIP	1	233	January 5, 2024
PJSIP calling SIPS endpoint using TLS leads to immediate BYE upon call pickup Asterisk SIP	4	540	March 20, 2024
In 180 ring missing contact info Asterisk SIP	35	840	August 4, 2023

Options Ping Contact Needs FQDN Instead of IP Address

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