SIP ALG (Application Layer Gateway) is a feature which is enabled by default in most Technicolor routers and inspects VoIP traffic as it passes through and modifies the messages on-the-fly.

In few situations this is useful, but in most situations SIP ALG can cause problems using the service. Very often, SIP ALG is poorly implemented causing VoIP messages to be modified in a harmful way or simply corrupts them. In such cases you may experience issues registering your handset, one-way or no audio, unable to receive calls, and issues with Busy Lamp Field (BLF) and Message Waiting Indicators (MWI).

This guide explains how to disable SIP ALG on the following models:

• Technicolor TG582n PRO
• Technicolor TG582n SB
• Technicolor TG589vn V3
• Thomson TG585 v7 and TG585 v8

For the Technicolor TG589VAC or Technicolor TG588v v2 please see this guide.

1. Press the Windows Start button and in the search box type in cmd and hit Enter
2. Type in
   

   telnet 192.168.1.254

   and hit Enter
   Note Windows Vista/7 may not have Telnet installed by default. Please click on Start → Control Panel → Programs → Programs and Features → Turn Windows Features on or off → Ensure TELNET CLIENT is checked and click OK.

3. When prompted, the default username is Administrator and the default password is the serial number
   Note that no symbols may appear when typing in the password, but continue anyway.
   Also note that the username and password is case-sensitive.
4. Type in
   

   connection unbind application=SIP port=5060

   and hit Enter
   

5. Type in
   

   saveall

   and hit Enter to apply and make this setting permanent.

6. Type in

   exit

   and hit Enter to exit.

Different Technicolor routers may have different instructions. Please see list below for instructions for your particular device.

For further information please contact the retailer from whom you purchased the Technicolor router.

If you purchased the Technicolor from SureVoIP then SIP ALG will already be disabled.

We suggest purchasing a router more suitable for business use with a better security track record, such as a DrayTek router. Contact us and we will be happy to provide a quote.