Goal

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Routing of inter domain sessions over a TLS encrypted link between a SER and an OpenSER proxy 

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      User Agent A   ->   proxy domainA   ->   proxy domainB   ->   User Agent B

Prerequisites

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• Both proxies should have TLS enabled between themselves and connected UAs. 
• TLS is enabled for the SER proxy: see 3.16. TLS for SER (UA-Proxy)
• TLS is enabled for the OpenSER proxy: see 3.17. TLS for OpenSER (UA-Proxy)
• A PKI certificate is available that contains the full DNS name of the SIP proxy in the CN field (in this example "sipserver.domainA.net") and a corresponding certificate chain. Using out-of-the-box certificates that come as an example with the default installation of (Open)SER cannot be trusted.

Configuration  

OpenSER proxy configuration:

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