Disable SIP ALG to improve ServiceTitan call quality

  • Published on Apr 26, 2026
  • 8 minute(s) read
Prev Next

Overview

Use this article to turn off the Session Initiation Protocol Application Layer Gateway (SIP ALG) on your router or firewall. Disabling it helps prevent dropped calls, one-way audio, and failed transfers in ServiceTitan.

Who uses this feature

  • Administrators

  • Applies to all business types

  • Applies to all trades

Things to know

  • SIP ALG is a network setting on your router or firewall that tries to help VoIP traffic but often breaks modern cloud systems.

  • Disabling SIP ALG is done outside of ServiceTitan, on your network equipment.

  • If you are not comfortable changing network settings, contact your IT provider or ISP before making changes.

Key terms for this workflow

Session Initiation Protocol Application Layer Gateway (SIP ALG)

A feature on many routers that watches and edits internet phone (VoIP) traffic to help calls work through the firewall. Modern cloud phone systems like ServiceTitan already handle this themselves, so SIP ALG often breaks calls instead. This causes issues like one-way audio, dropped calls at set time marks, failed transfers, or phones that look registered but don't ring.

Network Address Translation (NAT)

A function on your router that lets many devices in your office (each with its own private IP address) share a single public IP address on the internet. It works like a doorman in an apartment building, keeping track of which device requested what, and normally works well with VoIP until extra features like SIP ALG start changing what's inside the call traffic.

Packets

Small chunks of data that carry information across the internet, each with a payload and a header. Payload contains the content, such as part of a web page or a tiny slice of voice audio and the header shows where it came from and where it's going. Routers usually only read the header to move packets along, but features like SIP ALG open them up and rewrite call details inside, which is what can cause ServiceTitan call problems.

Disable SIP ALG for your network

Step 1: Confirm this workflow applies to you

You might need to disable SIP ALG if you see one or more of these symptoms:

  • Calls where only one side can hear audio.

  • Calls that drop at a consistent time, such as 10 seconds or 15 minutes.

  • Transfers that fail immediately when you send a call to a colleague.

  • Phantom calls that appear in logs but never ring a device.

Step 2: Identify your router or gateway

  1. Find the main router or gateway that provides internet to your office. This might be an ISP-branded device (for example, AT&T, or Verizon) or a separate business router.

  2. Look for the manufacturer and model number on the label. You'll use this to find the correct section below.

Step 3: Log in to your router

  1. From a computer connected to your office network, open a web browser.

  2. In the address bar, enter the router's IP address. Common addresses include:        

    • 192.168.1.1

    • 192.168.0.1

    • 10.1.10.1

  3. When prompted, enter the administrator username and password.        

    • Check the label on the device or your IT documentation.

    • If you don't know the credentials, contact your IT provider or Internet Service Provider.

Step 4: Turn off SIP ALG (generic steps)

Use these general steps if your router brand is not listed below or if the menus look different.

  1. After you sign in, go to the advanced configuration or firewall area. Look for menu names such as:        

    • Advanced

    • Firewall

    • Security

    • WAN

    • NAT or NAT Passthrough

  2. In that area, look for a setting named SIP ALG or similar. Common names include:        

    • SIP ALG

    • SIP Passthrough

    • SIP Helper

    • SIP Transformations

    • VoIP ALG

  3. Turn the SIP ALG setting off.

  4. When finished, save your changes.

  5. Reboot your router if there is an option to do so. If not, you can power-cycle it manually.

If your router does not show any SIP ALG or VoIP ALG setting, check the manufacturer's support site or contact your IT provider.

Disable SIP ALG by router brand

Note: This information is sourced from manufacturer websites and user forums and has not been independently verified by ServiceTitan. The steps for your specific model or batch may differ. You may need to contact the manufacturer or your Internet Service Provider, or consult additional online resources, to get the current instructions.

Router Manufacturer

Steps to Disable SIP ALG

Actiontec

  1. In the router menu, go to Advanced.

  2. Confirm any warning that appears.

  3. Select ALGs.

  4. Ensure SIP ALG is turned off.

  5. Click Apply.

  6. (Optional) Return to Advanced and select Remote Administration if needed for your IT team.

Adtran

  1. In the web interface, go to Firewall > Firewall or ACLs.

  2. Select ALG Settings.

  3. Turn SIP ALG off.

  4. Click Apply.                        

    Tip: If you manage Adtran devices by command line, work with your IT provider to run the following command: no ip firewall alg sip.

Arris

Most Arris gateways

  1. In a browser, go to http://192.168.0.1.

  2. Log in with the administrator username and password.

  3. Go to Advanced > Options.

  4. Unselect SIP to turn SIP ALG off.

  5. Click Apply.

Arris BGW210

  1. In a browser, go to http://192.168.1.254.

  2. Authenticate using the Device Access Code from the modem label.

  3. Go to Firewall > Advanced Firewall.

  4. Turn SIP ALG off.

  5. Turn Authentication Header Forwarding off.

  6. Turn ESP Header Forwarding off.

  7. Save your changes.

Asus

  1. In the side menu, under Advanced Settings, select WAN.

  2. Click the NAT Passthrough tab.

  3. Set SIP Passthrough to Disable.

  4. Click Apply.

AT&T U-verse Pace 5268AC gateway

This device does not allow you to turn off SIP ALG directly.

  1. Contact AT&T or your IT provider.

  2. Ask them to put the AT&T gateway in Bridge Mode or IP Passthrough mode so it acts only as a modem.

  3. Have them install a separate business-grade router behind it.

  4. Disable SIP ALG on the new router using that manufacturer's instructions.

Cisco

Work with a qualified IT provider before running CLI commands on Cisco equipment.

General or enterprise-class Cisco routers

  1. On the device CLI, enter configuration mode.

  2. Run:                        

    1. no ip nat service sip tcp port 5060

    2. no ip nat service sip udp port 5060

Cisco PIX

  1. On the device CLI, enter configuration mode.

  2. Run:                        

    1. no fixup protocol sip 5060

    2. no fixup protocol sip udp 5060

Cisco ASA

  1. Find policy-map global_policy.

  2. In class inspection_default, run no inspect sip.

  3. Save the configuration.

D-Link

General D-Link routers

  1. In the web interface, go to Advanced Settings.

  2. Find the Application Level Gateway (ALG) Configuration section.

  3. Clear the SIP setting.

  4. Save your changes.

D-Link DIR-655 example

  1. Go to Advanced > Firewall Settings.

  2. Clear Enable SPI.

  3. Set UDP Endpoint Filtering and TCP Endpoint Filtering to Endpoint Independent.

  4. In Application Level Gateway Configuration, clear SIP.

  5. Save your changes and reboot the router.

Fortinet

Work with your IT provider before changing firewall helpers on Fortinet devices.

  1. Use the following commands from the CLI interface:                        

    1. config system session-helper

    2. show system session-helper

  2. Identify the entry for SIP (often entry 12) and delete it. Example: delete 12.

  3. Confirm its deletion by executing this command:                        

    1. show system session-helper

Linksys

Linksys Smart Wi-Fi (E-series)

  1. In the side menu, select Connectivity.

  2. Click the Administration tab.

  3. In the Application Layer Gateway section, clear SIP.

  4. Save your changes.

Older Linksys models

  1. Go to the Advanced section of the admin screen.

  2. Disable the SIP ALG feature.

Mikrotik

On Mikrotik devices, SIP ALG is called SIP Helper.

Winbox GUI

  1. Go to IP > Firewall.

  2. Click the Service Ports tab.

  3. Disable SIP.

Tip: You may also run this command from the terminal: /ip firewall service-port disable sip.

Netgear

Netgear Genie interface

  1. Click the Advanced tab.

  2. Expand Setup and select WAN Setup.

  3. Check Disable SIP ALG.

  4. Save your changes.

Other Netgear models

  1. Under Security or Firewall, open Advanced Settings.

  2. Turn SIP ALG off.

  3. Find Session Limit or UDP timeout settings.

  4. Increase the UDP timeout to 300 seconds.

  5. Save and reboot the router.

SonicWall

  1. In the menu, go to System Setup > VoIP.

  2. Select Enable Consistent NAT.

  3. Clear Enable SIP Transformations.

  4. Click Accept to save.

  5. To adjust UDP timeouts, go to Firewall Settings > Flood Protection.

  6. On the UDP tab, set the default UDP connection timeout to 300 seconds.

  7. Click Accept.

TP-Link

Newer TP-Link (Archer series)

  1. Click the Advanced tab.

  2. Select NAT Forwarding.

  3. Turn SIP ALG, RTSP ALG, and H323 ALG off.

  4. Click Save.

Older TP-Link devices (Telnet)

  1. Connect to the device via Telnet.

  2. Run ip nat service sip sw off.

  3. Save your configuration and reboot the router if needed.

UBEE

  1. In the router interface, go to Advanced > Options.

  2. Disable SIP and RTSP.

  3. Click Apply.

Ubiquiti

UniFi Security Gateway (USG)

  1. Sign in to the UniFi controller.

  2. Go to Routing & Firewall.

  3. Select the Firewall tab, then Settings.

  4. Disable H.323 and SIP.

  5. Click Apply Changes.

EdgeRouter (ER-X and similar)

Config Tree

  1. In the web UI, select Config Tree.

  2. Go to System > Conntrack > Modules > Sip.

  3. Select Disable.

  4. Click Preview, then Apply.

CLI

  1. From the administrative interface, select CLI.

  2. Enter these commands into the terminal:                        

    • Configure

    • set system conntrack modules sip disable

    • set system conntrack timeout udp stream 300

    • set system conntrack timeout udp other 300

    • Commit

    • Save

    • Exit

Verizon FiOS G1100

This device does not allow you to disable SIP ALG directly.

  1. Contact Verizon or your IT provider.

  2. Ask them to configure the FiOS gateway to act as a modem only.

  3. Install a business-grade router behind it.

  4. Disable SIP ALG on the new router using that manufacturer's steps.

ZyXEL

ZyWALL / USG60

  1. In the web interface, go to Configuration.

  2. Select Network > ALG.

  3. Turn Enable SIP ALG and Enable SIP Transformations off.

  4. Click Apply.

ZyXEL C1000Z / C1100Z (CenturyLink)

  1. Go to Advanced Setup.

  2. Select SIP ALG.

  3. Set SIP ALG to Disable.

  4. Click Apply.

ZyXEL P600 (Telnet)

  1. Open a Telnet session to 192.168.1.1 and log in with the device password. The default password is 1234.

  2. Type 24 and press Enter.

  3. Type 8 and press Enter.

  4. Run: ip nat service sip active 0

  5. Press Enter again and exit.

Reboot and test ServiceTitan calls

  1. After you turn SIP ALG off, reboot your router or firewall.

  2. Reboot your desk phones and any computers running a softphone.

  3. Sign in to ServiceTitan and open your Contact Center Pro or softphone workspace.

  4. Place several test calls:        

    • Inbound calls to your main line.

    • Transfers between agents.

    • Outbound calls to external numbers.

  5. If calls complete successfully without one-way audio, drops, or failed transfers, SIP ALG is likely resolved.

If issues continue, share this article and your test results with your IT provider or VoIP vendor so they can review other network causes (QoS, bandwidth, or cabling).

Want to learn more?

Related articles