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VOIP Troubleshooting Guide

Overview

Voice over IP, or VOIP, is becoming increasingly more popular as a low cost alternative to traditional land-line phones. However, there are many questions that may arise regarding deployment and usage. This document contains a list of frequently asked questions regarding the setup of VOIP through eSoft's InstaGate and the associated configurations that may need to be placed.

This article is intended to be an informal checklist of items to check on the InstaGate device when VOIP service is not working or performing poorly once deployed.

Configuration

• Enable SIP/VoIP
  1. Go to Firewall -> SIP/VoIP Settings.
  2. Enable SIP VoIP
      
• Check the Ports
  1. In SIP/VoIP Settings specify the SIP and RTP Port numbers. The standard ports are entered by default.
     • The default SIP port is 5060
     • The default RTP Port range is 7070-7089
        
  2. If you prefer not to use the SIP/VoIP Settings, you can also create custom services for the ports you wish to use.
     • Do not specify a source port unless explicitly told to do so by your VoIP Provider
     • If using a different port on your internal equipment than what is coming in on the initial request, enable the Redirect Port option in the custom service and specify the internal port number.
        
• Does the Provider Expect Return Traffic From the Same IP Address That They Send to?
  1. If they do, create a Source NAT rule to have outbound traffic appear to be coming from the WAN IP address

Troubleshooting

If using a non-standard port number, try switching to port 5060. Often the service provider will broadcast both the custom and default ports and this will help to determine if traffic is even reaching your network.

Troubleshooting VoIP connectivity can be tricky and often the simplest way to find the root source of trouble is to contact technical support and have them logged in and watching traffic.