SIP over the internet with CME

Unanswered Question
Jan 17th, 2008

I am going on CME 4.2 and CUE 3.1.1, I want to setup from remote end using Cisco IP phone SIP to register to CME via the Internet.

Remote end is using Linksys WRT160N router

Note: No VPN tunnel

I have this problem too.
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Paolo Bevilacqua Thu, 01/17/2008 - 09:19

Sure, it's possible. Be aware that if you have nat and/o rfw between internet and CME router, you can need additional configuration.

Also be aware that due the nature of CME works, anyone can place calls, so use ACL to restrict SIP to the addresses you want.

Hope this helps, please rate post if it does!

Logicalis Manag... Thu, 01/17/2008 - 09:29

you mention about additional configuration, what are those.

ACL to restrict SIP call?

In LAN SIP phones are working okay and here is my configuration.

Paolo Bevilacqua Thu, 01/17/2008 - 09:46

That would configuration on NAT/FW device to allow SIP calls.

If the CME interface is directly connected to the internet, you will need an ACL to restrict SIP only from known addresses. I understand this is a limitation when the address is not known in advance, unfortunately configuring authentication for incoming calls is quite complicated, requiring radius, etc.

Logicalis Manag... Thu, 01/17/2008 - 16:13

Right now, SIP can register via the Internet but I have one way audio typical routing issue and NATing. Can you help me with this

Paolo Bevilacqua Fri, 01/18/2008 - 02:35

You need to configure NAT/FW to allow audio to pass.

Cisco devices do that automatically, no configuration needed. Other makers require configuration.


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