Router Configuration - SIP ALG
Router Configuration for HostMyCalls
If you use high-speed internet service with HostMyCalls, a router feature called SIP ALG may need to be disabled.
Although SIP ALG is designed to help VoIP traffic pass through a router, many implementations interfere with SIP signaling and audio streams, causing call quality problems.
• SIP ALG stands for Session Initiation Protocol Application Layer Gateway
Why SIP ALG Should Be Disabled
When enabled, SIP ALG can modify SIP packets in ways that disrupt VoIP connections. Common symptoms include:
• Dropped or failed calls
• One-way audio
• Voice delay or jitter
• Poor call quality
• Phones failing to register or stay registered
Disabling SIP ALG is a widely recommended best practice for reliable VoIP performance.
What to Check During Setup
1. Confirm whether SIP ALG is enabled on your router
• SIP ALG is often enabled by default.
• Access your router’s admin interface to check.
2. If enabled, disable SIP ALG
• This is a key step for stable VoIP service.
• Save changes and reboot the router after disabling.
3. Verify after disabling:
• Test call registration and audio quality
• Monitor for dropped calls or latency issues
How This Is Typically Handled
During Installation
If an internet technician is installing or configuring your service, they can usually disable SIP ALG during setup if instructed ahead of time.
Provide them with the exact model of your router so they can locate the SIP ALG setting.
Self-Configuring Your Router*
• Log into the router’s administrative panel.
• Locate SIP ALG or Application Layer Gateway settings — often under:
○ Advanced → NAT → ALG
○ Security → Firewall
○ WAN / NAT / SIP
• Uncheck or turn off any options labeled:
○ SIP ALG
○ SIP Passthrough
○ SIP Helper
○ SIP Transformations
• Save settings and reboot the router.
*Refer to your hardware documentation.
Router Without a SIP ALG Option
• Some consumer devices do not expose a SIP ALG setting at all; you may need to:
○ Contact your ISP to see if they can disable it remotely
○ Replace the router with a model that allows SIP ALG control
○ Use SIP over TLS (which can reduce ALG interference)
Existing Service With Call Issues
If your internet service is already installed and you’re experiencing voice latency, dropped calls, one-way audio, or poor call quality:
• Log into your router and confirm SIP ALG is disabled.
• If you cannot find the option, contact your ISP support team and ask whether SIP ALG can be disabled on their equipment.
• Also verify firewall and NAT settings aren’t blocking or interfering with SIP ports
• Optionally consider:
○ Using SIP over TLS (helps with ALG on some routers)
○ Replacing the default router with one that has better SIP/VoIP support
Best Practices After Disabling SIP ALG
• Reboot the router after changes.
• Verify call quality and registration stability over several test calls.
• If problems persist:
○ Check firewall rules/port forwarding
○ Increase UDP timeout values
○ Consider router firmware updates
