How To Easily Disable SIP ALG On Any Router

common router close up

Should You Disable SIP ALG?

You might be wondering if you should turn your SIP Application Layer Gateway (ALG) on or off. The short answer is that you should keep it off. This is not the default factory setting for your router, so you need to get in touch with your IT service provider or to follow the instructions that come with your specific router model to turn it off.

Leaving the SIP ALG on can create a host of problems at inopportune moments, such as cutting off your business conversations, blocking incoming calls or failing to set up two-way audio transmissions.

How to Disable SIP ALG

The Juxto support team can help you configure your router so the SIP ALG won’t interfere with your phone calls. This support is not under our standard support services and requires scheduling a technical support call and will be charged at your standard professional services rate. Otherwise, we recommend asking your IT provider for help before configuring your device.

Most routers have their own set of rules for configuring SIP ALG. If you want to disable SIP ALG for your router, locate its brand and model in the alphabetical table below and follow the listed instructions.

Disclaimer: You should consult with an IT or network professional before changing your router’s configuration to avoid any problems.

Instructions by Model

  1. Use the command: no ip firewall alg sip
  1. Find the ‘Options’ listed under ‘Advance’ and uncheck the SIP box.
  2. Use the credentials:
    Username: admin
    Password: motorola
  1. Find ‘Class inspection_default’ listed under ‘Policy-map global_policy’.
  2. Use the command: no inspect sip
  1. Find ‘Class inspection_default’ listed under ‘Policy-map global_policy’.
  2. Use the command: no inspect sip

You cannot disable SIP ALG.

  1. Find the ‘SIP ALG’ listed under ‘NAT’ or ‘Router firewall settings’ and disable it

The disable SIP ALG option is available only for BT Business Hub versions 3 or higher.

  1. Find the SIP Fixup
  2. On General Routers, use:
    – no ip nat service sip tcp port 5060
    – no ip nat service sip udp port 5060
  3. On Enterprise-Class Routers, use:
    – no ip nat service sip tcp port 5060
    – no ip nat service udp port 5060
  4. On Pix Devices, use:
    – no fixup protocol sip 5060
    – no fixup protocol sip udp 5060
  1. Find ‘Application Level Gateway (ALG) Configuration’ listed under ‘Advanced settings’
  2. Click the ‘SIP’ option to uncheck it.
  1. For Vigor2760 routers, use the ALG feature listed under ‘Network/NAT’.
  2. For other DrayTek routers, use a Telnet client.
  3. For Windows operating systems:
    – Press the Windows Start Button
    – Search for ‘cmd’ and press enter
    – Type in telnet 192.168.1.1 and press Enter

Note: If the Windows telnet client is not installed on your system, you will have to find the Telnet Client in ‘Windows Programs and Features’ to turn it on.

  1. Enter your username and password in the credentials prompt.
  2. Use the commands:
    – sys sip_alg 0
    – sys commit
  3. For Draytek Vigor2750 and Vigor2130 routers use the commands:
    – kmodule_ctl nf_nat_sip disable
    – kmodule_ctl nf_conntrack_sip disable
  1. On the CLI interface, use the commands:
    – config system session-helper
    – show system session-helper
  2. Locate the SIP session instance, usually indicated by #12
  3. Delete #12 or the SIP session’s appropriate number
  4. Confirm the deletion by re-running ‘show system session-helper’.
  1. Find the SIP ALG in the router’s Security menu.
  1. For most Linksys routers, you have to find the ‘Advanced’ section on the ‘Admin’ page and disable the ALG feature.
  2. For the Linksys BEFSR41 router, find the ‘Port Triggering’ section listed under ‘Applications and Gaming’ on the Admin page.
    – Put ‘TCP’ as the application.
    – Put ‘5060’ into the Start Port and End Port for both the ‘Triggering Range’ and ‘Forwarded Range’ fields.
    – Check ‘Enable’.
    – Save your settings and Reboot.
  1. Disable the SIP Helper.
  1. In the admin interface, find the advanced settings listed under ‘Security/Firewall’.
  2. Disable the SIP ALG.
  3. Find the ‘Session Limit’ listed under ‘Security/Firewall’.
  4. Increase the ‘UDP timeout’ to 300 sec.
  1. Find the VoIP tab
  2. Make sure the ‘Enable Consistent NAT’ setting is checked
  3. Make sure the ‘Enable SIP Transformations’ is unchecked.
  1. Check your router’s user manual to see if you have to use Telnet commands to disable SIP ALG.
  1. Type cmd in the Windows Start menu to use the Telnet client
  2. Use the command: ip nat service sip sw off
  1. Go to the ‘Advanced’ tab listed under ‘Options’.
  2. Make sure the SIP option is unchecked
  3. Make sure the RTSP option is unchecked.
  4. Click ‘Apply’.

You cannot disable SIP ALG.

  1. Find ‘ALG’, listed under ‘Network/Configuration/Settings’.
  2. Disable SIP ALG.

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