Solved

Remote softphone cannot register to LAN PBX via VPN

Posted on 2013-05-23
3
649 Views
Last Modified: 2013-06-04
Hi all,
Appreciate in advance if anyone can help me this problem.
My office has one Juniper SSG5 firewall.
For remote users, I install Shrew soft VPN client for their remote access.
Users have no problem use VPN access LAN share drive or RDP to office desktop.
However users' softphone cannot register to LAN PBX through VPN.
I use wireshark and get attached result.
10.0.30.209 is VPN client.
10.0.1.180 is IP PBX.
From the capture, it shows Destination port: vat
I don't know what does that mean. Can somebody please give me a hint or direction for troubleshooting?

Thanks,
Vince
Capture.JPG
0
Comment
Question by:generait
3 Comments
 
LVL 5

Assisted Solution

by:Eikroman
Eikroman earned 250 total points
ID: 39193779
Hello,

vat, in Wireshark is probably port 3456 (examine the packet to make sure). It may be used in SIP.

Anyway, if there is no restrictions on VPN clients communication, the problem is most likely in the SIP client software/configuration.

I have seen a situation where SIP client couldn't correctly handle VPN connection.
SIP client erroneously binded itself to the regular internet connection interface and tried to contact internal VPN IP over Internet, which of course didn't work. In our case, it was a software bug.

It's easily detectable on client side using Wireshark by checking on which interface SIP client tries to communicate. On server side, there will be no or partial handshake.
0
 
LVL 23

Accepted Solution

by:
Mohammed Hamada earned 250 total points
ID: 39199208
VAT on 3456 (default port) is a Video/Audio (tool == vat) conferencing protocol but I don't think you need it in this case.

In your PBX network settings, have you configured the gateway IP to be pointing to the firewall Local IP so your users can register to the PBX through the firewall ? Because when the phone registration request is sent through the VPN it will first go to the firewall while holding the registrar IP address and if your PBX doesn't have the Gateway IP address set as your Firewall's Local IP then the firewall will not be able to route the registration request there.

Where did you use wireshark btw? On the PBX or on the client PC? U have to use it on both and check for SIP requests. what does the invite looks like.
please attach the log here so we can see but after you make sure that PBX's gateway is pointing to the firewall's Local IP.
0
 

Author Closing Comment

by:generait
ID: 39220384
Thanks for your reponse.
Finally the PBX vendor modified system parameters then solved the issue.
The networking has no problem in this situation.
Again thanks for all inputs.
0

Featured Post

Superior storage. Superior surveillance.

WD Purple drives are built for 24/7, always-on, high-definition security systems. With support for up to 8 hard drives and 32 cameras, WD Purple drives are optimized for surveillance.

Join & Write a Comment

Envision that you are chipping away at another e-business site with a team of pundit developers and designers. Everything seems, by all accounts, to be going easily.
This paper addresses the security of Sennheiser DECT Contact Center and Office (CC&O) headsets. It describes the DECT security chain comprised of “Pairing”, “Per Call Authentication” and “Encryption”, which are all part of the standard DECT protocol.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

758 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

23 Experts available now in Live!

Get 1:1 Help Now