From: Duane Dewitt (Duane.Dewitt@za.verizonbusiness.com)
Date: Wed Aug 23 2006 - 03:54:03 ART
Hi
It is indeed a NAT issue and is very well documented on CCO. Basically
the IP header is being translated but the H323 header is not. If you do
a H323 debug you will see that the destination IP address is the
original address and not the translated one. Cisco's recommended
solution is to run a Cisco device for NAT which is capable of
translating the H323 header as well. I think that SIP may also solve
this, but haven't tried that.
Do a search on CCO for one way voice and you'll get a wealth of
knowledge around it.
Regards
Duane
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Julius Kinsler
Sent: 22 August 2006 05:26 PM
To: ccielab@groupstudy.com
Subject: OT: NAT and VOIP
I am having a heck of a time with a CME and a client that uses IP Blue
or IP communicator via VPN. I believe it may be a voice RTP issue's with
a VPN endpoint, but I am only able to get one way voice whereas the
person using the software client cannot hear me but I can hear them.
I have a been testing using myself as and the endpoint that will first
"using Cisco VPN client s/w" VPN to a IOS router with CME-F/W features.
We they start up IP blue or IP communicator. This will register with the
CME system. But when we make calls to internal users or through the PSTN
we can not hear either party's conversation. This I think tells us that
the TCP is working (signaling) correctly but the UDP is not. I believe
this to be a NAT and UDP-RTP problem but cannot get my hands around it.
I believe this is a problem with NAT and VOIP. Am I completely off base
about this or what? If this is so I dont know what to do to solve this
issue.
Any help would be very much appreciated. BTW, When I bring the software
client in house on the local LAN the software works 100%.
This article explains my problem well but does not offer an acceptable
solution:
http://www.voip-info.org/wiki-NAT+and+VOIP
Thanks
Julius B. Kinsler
Network Engineer | Harbor Technologies
phone: 856.533.6021 | e-mail: Jkinsler@harbortech.com
<blocked::mailto:Jkinsler@harbortech.com>
9000H Commerce Parkway
Mt. Laurel, NJ 08054
Visit our website at:
www.harbortech.com <http://www.harbortech.com/> Engineering Services for
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