SIP Trunking Troubleshooting 

Below you can find some common issues you might encounter when configuring your SIP device to our SIP trunking services.  If you would like help configuring your VoIP/SIP device, check out our VoIP Sample Device Configuration page.  There you will also find help with configuration example for different flavors of Asterisk PBX.

Topics

Asterisk Troubleshooting

How do I register my SIP phone to my Asterisk PBX?

Issue:  I want to register my phone via SIP to my Asterisk pbx.
Resolution: SIP phone registration allows a SIP phone to communicate with it's PBX "Yo PBX, I am Jack's phone... and my username and password is.....  and if you get any calls that are for me, send them to this IP address."

You might be able to find information regarding setting up your specific model phone in or Sample Config page.  However, this is a list of common settings you'll need to place in your phone's settings:

  • Registrar/Registration Server - The location of the server which the phone should register to. This should be set to the IP address of your Asterisk system.
  • SIP User Name/Account Name/Address - The SIP username on the remote system. This should be set to demo-alice on one phone and demo-bob on the other. This username corresponds directly to the section name in square brackets in sip.conf.
  • SIP Authentication User/Auth User - On Asterisk-based systems, this will be the same as the SIP user name above.
  • Proxy Server/Outbound Proxy Server - This is the server with which your phone communicates to make outside calls. This should be set to the IP address of your Asterisk system.

Asterisk returns 'Request Sent' but never registers.

Issue:  Incorrect email address sent
Resolution: Verify 'Advanced SIP Settings' to ensure that the correct IP address is being sent.Address.

How To Debug and Troubleshoot Asterisk PBX (SIP)

Issue:  I want to view my SIP messaging so that I can trouble shoot my Asterisk PBX.
Resolution: One of the primary techniques is to view what is actually getting sent and received by VOIP devices. There are several ways to do this:

  • Monitor Ethernet Traffic
  • Debugging displays from a VOIP program

There are several free SIP debuggers available online.  Visit VoIP-Info has a great list of available ethernet and monitoring and test tools) (https://www.voip-info.org/wiki/view/How+To+Debug+and+Troubleshoot+VOIP)

Also, it helps to understand whats supposed to be happening. Studying the relevant RFCs and other protocol documents and tutorials is helpful.


Common SIP Error Codes

488 Not Accepted Here (Codec Mismatch)

Issue: Codec mismatch or codec resource unavailable.  IPComms only supports G.729 and G.711 codecs
Resolution: Check that you have codecs G.729 or G.711 activated on your PBX.

503 Service Unavailable (Concurrent Call Limit Reached)

Issue: Your account has reached its call capacity limit. 
Resolution: Order additional SIP trunk lines for your account or reduce the volume of calls.

401 Service Unauthorized (IPComms server can not authenticate the SIP user)

Issue: Bad SIP username and/or password
Resolution: Verify that you are using the correct SIP username and password for your particular IPComms SIP trunk.

Issue: Firewall blocking SIP request
Resolution: Verify that you have whitelisted IPComms SIP servers and IP Addresses in your PBX and firewall.

404 Target is unknown or can’t be found (bad number format).

Issue: Incorrect number format
Resolution: Ensure that you are sending your calls with preceding "1".  (e.g. 1-6784601475, not  6784601475) for all outbound calls.


Call quality issues

I am experiencing poor call quality.

Issue: Jitter is one of the most common VoIP call quality problems.
Resolution: Jitter is the variability over time of the latency across a network.  Speak to your Internet service provider about normalizing network latency.  Network hardware can also be a possible issue.  Check your network router and firewall quality and configuration.  

Issue: Poor Internet Connection
Resolution: Check your Internet quality.  Try running PING tests and network traceroutes to check the quality of your Internet connection.  If you need assistance, you can contact a member of our support team to help you isolate network issues.  In addition, contact your ISP for assistance with network quality issues.

When I make a call, the other party can't hear me, but I can hear them (or vice versa).

Issue: Your firewall is blocking outbound RTP packets to IPComms
Resolution: Ensure your firewall is configured to allow RTP from your PBX.

Issue: Your PBX is using your LAN IP address rather than your Wan IP address for SDP.
Resolution: Ensure your PBX is setup to use the WAN IP address for SDP.

Issue: Your PBX and our network cannot agree on a common codec.
Resolution: Ensure that your PBX has G.729 and G.711 codecs enabled.

I am experiencing echo on my calls.

Issue: Your firewall is blocking outbound RTP packets to IPComms
Resolution: Speaker phones are very prone to echo. Try asking the other party to turn the volume down on their phone. If they are using a speaker phone see if lowering the speaker volume or picking up the handset eliminated the echo.


Origination calls (from PSTN to your PBX)

Calls are reaching my PBX, but they are being rejected by my PBX or timing out.

Issue: Your PBX does not have the IPComms proxy IP addresses allowed (whitelisted) in your firewall.
Resolution: Confirm that the SIP URI is correct in your PBX origination settings.
Resolution: Be sure that IPComms IP addresses and ports are whitelisted in your PBX (if applicable).
Resolution:Be sure that IPComms IP addresses and ports are whitelisted in your Firewall (if applicable).

I can't place receive inbound calls.

Issue: The SIP ID and password aren’t correct.
Resolution: Check the SIP ID and password on the phone.

Issue: There are NAT issues on the firewall or in the Asterisk configuration file. 
Resolution: Your personal firewall on your network might have NAT (network address translation) enabled, or it might be blocking the ports that need to be open for VoIP to communicate to the outside world. There are two types of traffic that need to be forwarded: SIP signaling and RTP media. The default port for UDP based SIP signaling is port 5060. The RTP media traffic (the actual audio stream) uses a range of 10000-20000.

Issue:  The SIP line isn’t registered.
Resolution: Verify your SIP account registration information in your provisioning letter sent in by IPComms upon sign-up.  Ensure it is the same in your device's SIP account settings.

When I make a call, the other party can't hear me, but I can hear them (or vice versa).

Issue: Your firewall is blocking outbound RTP packets to IPComms
Resolution: Ensure your firewall is configured to allow RTP from your PBX.

Issue: Your PBX is using your LAN IP address rather than your Wan IP address for SDP.
Resolution: Ensure your PBX is setup to use the WAN IP address for SDP.

Issue: Your PBX and our network cannot agree on a common codec.
Resolution: Ensure that your PBX has G.729 and G.711 codecs enabled.

I am experiencing poor call quality.

Issue: Jitter is one of the most common VoIP call quality problems.
Resolution: Jitter is the variability over time of the latency across a network.  Speak to your Internet service provider about normalizing network latency.  Network hardware can also be a possible issue.  Check your network router and firewall quality and configuration.  

Issue: Poor Internet Connection
Resolution: Check your Internet quality.  Try running PING tests and network traceroutes to check the quality of your Internet connection.  If you need assistance, you can contact a member of our support team to help you isolate network issues.  In addition, contact your ISP for assistance with network quality issues.

I am experiencing echo on my calls.

Issue: Your firewall is blocking outbound RTP packets to IPComms
Resolution: Speaker phones are very prone to echo. Try asking the other party to turn the volume down on their phone. If they are using a speaker phone see if lowering the speaker volume or picking up the handset eliminated the echo.

I am not seeing incoming calls reach my PBX.

Issue: You have either not configured an Origination SIP URI for your IPComms SIP Trunk, or have configured a “bad” SIP URI that does not resolve
Resolution: Check that you have configured your SIP URI correctly.


Outbound/Termination calls (Your PBX to PSTN)

I am not able to make any international phone calls.

Issue: International call termination is blocked by default by IPComms.
Resolution: Contact IPComms Customer Support, request that your account have international calling enabled, and by completing the Int'l verification process.

Calls to specific countries are not working.

Issue: You are attempting to make a call to a country that is not supported by IPComms.
Resolution: Contact IPComms Customer Support and verify available country access.

I can't place outbound calls.

Issue: The SIP ID and password aren’t correct.
Resolution: Check the SIP ID and password on the phone.

Issue: There are NAT issues on the firewall or in the Asterisk configuration file.
Resolution: Your personal firewall on your network might have NAT (network address translation) enabled, or it might be blocking the ports that need to be open for VoIP to communicate to the outside world. There are two types of traffic that need to be forwarded: SIP signaling and RTP media. The default port for UDP based SIP signaling is port 5060. The RTP media traffic (the actual audio stream) uses a range of 10000-20000.

Issue: The SIP line isn’t registered.
Resolution: Verify your SIP account registration information in your provisioning letter sent in by IPComms upon sign-up.  Ensure it is the same in your device's SIP account settings.

I'm not getting a response to my SIP requests.

Issue: Your firewall (at your location) is denying SIP requests to IPComms.
Resolution: Open SIP ports 5060 & 5061 on your firewall.

I am not able to place more than (x) calls at any one time.

Issue: You are exceeding your SIP trunk concurrent call capacity.
Resolution: Add more ports to your SIP trunk.


Account Sign up and Setup

I just signed up but I haven't received my user name and password

Issue:  I just signed up but I haven't received my user name and password.
Resolution: Check your spam folder in your email.  Ensure emails from ipcomms.net are allowed in your spam filter.  Your account will not be activated until we have successfully completed voice verification on the number you provided during sign-up.  Contact customer support to request another voice verification call.


Technical specs

CODEC SUPPORT

G.711 - Standard (64kbit/s per call)
G.729 - Compression (8kbit/s per call)

SIP Protocol Support

SIP -  (Session Initiation Protocol)- RFC3261
G.711 - Standard audio compression
G.729 - Efficient audio compression
FAX - T.38 & G711 Passthrough
DTMF - RFC4733, RFC 2833

Security

SIP Username/Password Authentication
Prefix-Based IP Authentication
IP-SEC (*service dependent)

CALL ROUTING

Basic SIP Endpoint Routing
PSTN Forwarding - mobile or landline
Dynamic Load-Balancing
Automatic Call Failover

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