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setting up IP telephony

setting up IP telephony

setting up IP telephony

Hello All

I got a problem, I am trying to setup IP telephony between two sites one of the sites has a firewall (main site) how can I set the firewall to let the IP's that belongs to telephoy pass through it I opened the UDP port but it didn't work , also can I use 2 networks one is for data users and the other for IP telephony if so how to configure it in the firewall my firewall has to NIC one inside and the one is for outside using NAT

I appreciate your help

RE: setting up IP telephony

I think we need more details, what kind of firewall etc.
Also, since this is basically a firewall question, you might be better of posting in another forum...

RE: setting up IP telephony

You mention that you opened the UDP port.  What about the TCP port(s) for call control?  Are you using SIP or H.323?  Is this a Cisco VoIP solution?

Can you describe the architecture in more detail?

As far as I know, you have two options.  One is to implement a VoIP-aware proxy in your firewall, which will open pin holes for the UDP traffic based on the Call Control information, and the other is to tunnel the VoIP traffic in a VPN.

From my experience, implmenting packet filtering (only) for VoIP is not very secure.


RE: setting up IP telephony

in my experience a vpn is the easiest and most secure method of doing what you want.  

you can segment voice traffic on each lan using vlans and vlan tagging.  this will also allow you to set a higher priority on voice packets since they are and need to be real time.

RE: setting up IP telephony

stevetotaro is right with the vpn's, by the way are these to locations tied together with point to point t-1's, wireless??  Which ip office console are you using, what type of router and switchs are you using?

RE: setting up IP telephony

Thanks guys for your reply's I am new in IP telephony and I dont know how to set it up in router and firewall using VPN, so the VPN setup will be between the cisco routers 2610 and the vLAN setup will be in Nortel switches it sound logic but is there another way without VPN ?

Thanks again guys for your help

RE: setting up IP telephony

Sorry for the late reply but I just read this thread and have a question about tunnelling H.323 through a VPN:

Won't VPN processing time create enough of a delay to degrade the audio?

RE: setting up IP telephony

No, the VPN processing is very small in comparison to the 250 - 300 ms of round trip delay that is considered acceptable to most people.


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