Hi,

I am troubleshooting some strange call setup problems using an Edgewater Networks SBC. A couple of Polycom phones sit behind the SBC and they connect to a SIP Server in the cloud. The SBC is in passthrough mode.

What I see that I am not sure about is:
INVITE from SIP Server to SBC IP (no Record-Route header...so far no surprise here)
INVITE from SBC to Phone (Record-Route header inserted by SBC but with the IP of the SIP Server)

I do not think the SBC is supposed to add a Record-Route header with the IP of the remote SIP Server. I think It should only be allowed to add Record-Route headers with its own IP. Does that sound right?

The RFC lists the usage as:

"20.30 Record-Route

The Record-Route header field is inserted by proxies in a request to
force future requests in the dialog to be routed through the proxy."

It says nothing about being able to arbitrarily force future requests to go through a remote IP.

Please advise.

Thanks,

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Technical Support