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

[rasheed_speechlogix]

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

[Dan Lukes]

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.

[rasheed_speechlogix]

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