topic Re: Configuring Cisco 8845 IP phone with MPP firmware for asterisk with SIP over TLS in Voice Systems and Accessories - Small Business

Configuring Cisco 8845 IP phone with MPP firmware for asterisk with SIP over TLS

rasheed_speechlogix — Sun, 13 Jun 2021 17:24:47 GMT

Hello ,

i have upgraded the migrated the firmware of Cisco 8845 IP phone from enterprise firmware to MPP firmware. Firmware migration went well and all seems good.. but when i tried to register the IP phone over SIP TLS to Asterisk PBX , it is always returning an error "UNKNOWN CA (48)" . i tried many methods to solve the issue , but nothing is successful . Attaching the Wireshark trace downloaded from the IP phone with this post. Any help to solve this issue would be highly appreciated.

Thanks

Abdul Rasheed

Re: Configuring Cisco 8845 IP phone with MPP firmware for asterisk with SIP over TLS

Dan Lukes — Sun, 13 Jun 2021 21:47:16 GMT

There are only way to solve "UNKNOWN CA" TLS error. The issuer of the server's certificate must be known to phone.

Based on the dump, server is using certificate /CN=pbx.zaincallstelephony.com issued by /CN=Asterisk Private CA

And /CN=Asterisk Private CA is the certificate that you need to configured as custom CA to phone.

Re: Configuring Cisco 8845 IP phone with MPP firmware for asterisk with SIP over TLS

rasheed_speechlogix — Mon, 14 Jun 2021 05:47:40 GMT

Hello Dan ,

Thanks a lot for your reply. I could find that there is an option in Cisco MPP phone's web portal to configure Custom CA Rule under

Voice -> provisioning menu. Is it expecting an http link to a client certificate from /CN=Asterisk Private CA and the certificate to be hosted under this link ?

Thanks and regards

Abdul Rasheed