Solved

VOiP Problems

Posted on 2012-03-28
6
225 Views
Last Modified: 2013-11-13
We have a VOiP server (Trixbox CE, freepbx server v2.6.2.3) with approximately 75 extensions.
The server is in a datacenter, connected directly to an external IP.
We have 4 offices, each office uses a Sonicwall Firewall (NSA 2400, TZ100, TZ210 and a TZ200)
We are encountering multiple problems

1.) No voicemail.  
The voicemail on the phone works fine most of the time, maybe 60%.
But other times we click on the voicemail button on our phones (Cisco SPA303)
There is no sound what so ever. Other times we can hear the computer voice asking for password, after the password is entered it says "you have x new messages" "to listen to your messages press one"
After pressing 1, no message is played and the computer voice says "to listen to your message again press 2" etc.
But if I log into the trixbox gui ,  I am able to listen to all messages there.

2.) IVR no sound
We have a IVR setup to route calls to specific extensions.
Sometimes when calling our main number there is no sound either.
I think the times are the same as the voicemail issue.

Please help,

Thank you
Armin
0
Comment
Question by:ascherkey
  • 3
  • 3
6 Comments
 
LVL 15

Expert Comment

by:Perarduaadastra
Comment Utility
A fruitful source of VoIP problems is firewall configuration, and in particular double NAT-ing between endpoints.
Because VoIP uses UDP there is no error checking and packets that are lost or dropped disappear without trace.

Have you looked at the SIP traces from the phones or run a PCAP to see what's happening?
Wireshark is excellent for this kind of work.
0
 

Author Comment

by:ascherkey
Comment Utility
I am not familiar with wireshark, how would I capture packages from a phone to the voip server?
I have been looking at Firewall forums, I found 2 articles, but when I changed the sonicwall setting accordingly, even more problems arose.
0
 
LVL 15

Expert Comment

by:Perarduaadastra
Comment Utility
Most phones have a utility for logging SIP traces built-in. My experience is mainly with Snom phones, and I have to say that I've never tinkered with a Cisco phone. Find the utility and try a short SIP trace first - just a few seconds, as quite a lot of data is generated.
You're looking for sending and receiving IP addresses that you're expecting, and the SIP status codes, eg: SIP/2.0 100 Trying.

A lot of what you see are unique identifiers, which aren't relevant to what you're trying to discover. However, the error messages should give at least a pointer as to the nature of the problem.

Regarding Wireshark, there is documentation here:

http://www.wireshark.org/docs/wsug_html_chunked/ChapterIntroduction.html

Section 3 deals with the interface and how to use it, but there is a lot of interesting stuff before you get there, though you are unlikely to need to know how to build it under Unix and Windows - I skip all that, and just download the latest stable release for the Windows platform. You may be a Linux, Mac, or Unix man, in which case you would use those versions.

Another question: What firewall installations does the datacentre have? Or are you expected to provide your own? Either way, the fact that all your branch offices are experiencing these problems but direct access to the Trixbox works fine, suggests that the problem is likely to be at the server end of the connection rather than the phones.

Has this problem been present ever since the installation went live, or has it happened recently? If the latter, what changed, and who changed it? Has your ISP made some changes and not told you?

Have you spoken to Sonicwall? As you have four different appliances of theirs (even though three of them are getting on a bit), they ought to be able to shed some light on how best to configure them for VoIP. At least they should be able to confirm that your present configurations are OK, or that they are contributing to the problem.
0
Better Security Awareness With Threat Intelligence

See how one of the leading financial services organizations uses Recorded Future as part of a holistic threat intelligence program to promote security awareness and proactively and efficiently identify threats.

 

Accepted Solution

by:
ascherkey earned 0 total points
Comment Utility
I tried all the above, nothing seems to fix the issue.
My last option is to switch the server. which i will do tomorrow
0
 
LVL 15

Expert Comment

by:Perarduaadastra
Comment Utility
Are you able to post any SIP traces?

The fact that sometimes the call is established but nothing can be heard suggests that the RTP stream has not been configured correctly. RTP is configured from information placed in the SIP packet body by SDP (Session Description Protocol), which defines such things as port numbers, codecs, protocols etc. If, for example, there is a request for a particular codec and one of the devices doesn't support it, then if an alternative can't be negotiated the media part of the call (that is, the speech) will fail and you won't hear anything.

Have you checked that everything is using the same codecs and protocols? Are some of the phones using SIP while others are trying to use secure SIP?

Without some more detailed information I can't really be of any help.
0
 

Author Closing Comment

by:ascherkey
Comment Utility
Was a hardware issue, installed new server, problem is resolved
0

Featured Post

Why You Should Analyze Threat Actor TTPs

After years of analyzing threat actor behavior, it’s become clear that at any given time there are specific tactics, techniques, and procedures (TTPs) that are particularly prevalent. By analyzing and understanding these TTPs, you can dramatically enhance your security program.

Join & Write a Comment

Does the idea of dealing with bits scare or confuse you? Does it seem like a waste of time in an age where we all have terabytes of storage? If so, you're missing out on one of the core tools in every professional programmer's toolbox. Learn how to …
A short article about problems I had with the new location API and permissions in Marshmallow
In this fourth video of the Xpdf series, we discuss and demonstrate the PDFinfo utility, which retrieves the contents of a PDF's Info Dictionary, as well as some other information, including the page count. We show how to isolate the page count in a…
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…

762 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

11 Experts available now in Live!

Get 1:1 Help Now