Sonicwall Configuration Guide

Introduction

This guide provides our recommended configuration for Sonicwall firewalls to ensure optimal VoIP performance.

✅ Quick Checklist: Signs Your Sonicwall Needs VoIP Optimization

If you notice any of the following, this guide is for you:

Symptom	Description
Phone deregistration	Phones showing "Not Registered" when they shouldn't
One-way audio	You can hear the other party, but they can't hear you (or vice versa)
Dropped calls	Calls disconnect after a specific time period
No incoming calls	Phone doesn't ring for incoming calls
Call transfer failures	Parties can't hear each other after transfers
Call hold issues	Audio doesn't return after placing a call on hold

Provider-Specific Requirements

Important: You need to configure the following settings on your Sonicwall firewall.

Requirement	Specification
IP Range to Whitelist	`64.26.133.64/27`
SIP-ALG Status	Must be DISABLED
Consistent NAT	Must be ENABLED

Core Configuration Steps

VoIP-Specific Settings (CRITICAL)

Critical: These settings MUST be configured exactly as shown. Incorrect settings will cause VoIP failure.

Navigation	Setting	Action
`VoIP > Settings`	Enable Consistent NAT	✅ CHECK
`VoIP > Settings`	Enable SIP Transformations	❌ UNCHECK (Disables SIP-ALG)

Bandwidth Management

Navigation	Setting	Value
`Firewall Settings > BWM`	BWM Type	`Global`
`Firewall Settings > BWM`	Realtime Bandwidth	✅ CHECK; Set to `30%` or `100 kbps x Max Calls`

Flood Protection

Navigation	Setting	Action
`Firewall Settings > Flood Protection > UDP`	UDP Flood Protection	❌ UNCHECK (Keep disabled)
`Firewall Settings > Flood Protection > UDP`	UDP Timeout Value	Change from `30` to `300` seconds

WAN Interface Bandwidth

Navigation	Setting	Action
`Network > Interfaces > Edit WAN > Advanced`	Egress Bandwidth (Upload)	✅ CHECK; Set to ISP Upload speed
`Network > Interfaces > Edit WAN > Advanced`	Ingress Bandwidth (Download)	✅ CHECK; Set to ISP Download speed

Pro tip: Verify your actual speeds using a reliable speed test before configuring these values.

Advanced Connection Timeouts

Navigation	Setting	Value
`Firewall Settings > Edit LAN > WAN Rule > Advanced`	TCP Inactivity Timeout	`60` minutes
`Firewall Settings > Edit LAN > WAN Rule > Advanced`	UDP Inactivity Timeout	`1800` seconds

IP Whitelisting

Create the following access rule to allow traffic from our servers.

Field	Value
Service	Any
Source	`WAN` / Network: `64.26.133.64/27`
Destination	`LAN` / Address Range: `* to *`
Comment	`NEW-VoIP-Provider-Subnet`
Advanced	Allow Fragmented Packets
	TCP Timeout: `60` minutes
	UDP Timeout: `1800` seconds

Note: The /27 notation includes 32 IP addresses ranging from 64.26.133.64 to 64.26.133.95.

✅ Configuration Checklist

#	Task
1	Consistent NAT Enabled
2	SIP Transformations Disabled (SIP-ALG off)
3	BWM configured (Global)
4	UDP Flood Protection disabled
5	UDP timeout set to `300` seconds
6	WAN bandwidth limits applied (Egress/Ingress)
7	TCP timeout set to `60` minutes
8	UDP timeout (advanced) set to `1800` seconds
9	Whitelist Rule created: `64.26.133.64/27`
10	All changes applied and configuration saved

Verification & Testing

SIP-ALG Verification Test

Test URL: http://mcstest.visualware.com/myspeed/myvoiph5_g711_sipalg.html

Item	Detail
Requirement	Download the BCS utility when prompted
Expected Result	`SIP ALG Firewall: N`
If Result Shows "Y"	SIP-ALG is still active. Revisit Section 2.1 and confirm SIP Transformations are UNCHECKED.

Functional Testing

Test Case	Procedure	Expected Result
Outbound Call	Place call to external number	Two-way audio established
Inbound Call	Call in from external number	Phone rings, call connects with two-way audio
Call Hold/Resume	Place call on hold, then resume	Audio returns successfully
Call Transfer	Transfer an active call	Transfer completes, parties can communicate

🚨 Quick Troubleshooting

Issue	Most Likely Cause	Solution
One-way audio	SIP Transformations enabled	Re-check Section 2.1
No incoming calls	Missing whitelist rule	Verify Rule exists and is active (Section 3)
Calls drop after ~30 seconds	UDP timeout too low	Confirm UDP timeout = `1800` seconds (Section 2.5)
Phones re-registering constantly	SIP-ALG interfering	Run SIP-ALG test; re-check Section 2.1

🛠️ Official Sonicwall Tutorials

For visual guidance on configuring your Sonicwall firewall, visit the official Sonicwall Video Tutorials page:

🔗 Sonicwall Tutorials

Documentation Index