SIP Configuration Guide

Configure your PBX or softphone to connect to IPComms SIP Trunking services.

SIP Server Settings

Use these settings to configure your trunk or SIP device:

Setting Value
SIP Server / Registrar sip.ipcomms.net
Outbound Proxy sip.ipcomms.net
SIP Port (UDP/TCP) 5060
SIP Port (TLS) 5061
Transport UDP (recommended), TCP, or TLS
Username Your SIP username (from portal)
Password Your SIP password (from portal)
Auth Username Same as Username
Registration Required (60-300 seconds)

Note: Your specific SIP credentials are available in the customer portal under SIP Trunking → Credentials.

Codec Configuration

Configure codecs in priority order for best quality:

Priority Codec Bandwidth Notes
1 G.711u (PCMU) 87 Kbps Best quality, recommended
2 G.711a (PCMA) 87 Kbps Equivalent quality, Europe standard
3 G.729 31 Kbps Low bandwidth, good for limited connections

DTMF Settings

DTMF Mode: RFC 2833 (recommended)
Payload Type: 101

Firewall Configuration

Open the following ports in your firewall for SIP and RTP traffic:

Purpose Protocol Port(s) Direction
SIP Signaling UDP 5060 Inbound & Outbound
SIP Signaling (TLS) TCP 5061 Inbound & Outbound
RTP Media UDP 10000-20000 Inbound & Outbound

Important: If you're behind NAT, ensure your PBX is configured to use STUN or has proper NAT traversal settings to avoid one-way audio issues.

NAT Configuration

If your PBX is behind a NAT router, configure these settings:

Option 1: External IP

Set your external (public) IP address in your PBX settings.

external_media_address = YOUR_PUBLIC_IP

external_signaling_address = YOUR_PUBLIC_IP

Option 2: STUN Server

Use a STUN server for dynamic NAT detection.

stun_server = stun.l.google.com:19302

Common NAT Issues

One-Way Audio

You can hear the caller, but they can't hear you (or vice versa).

Solution: Check NAT settings, verify RTP ports are open, ensure external IP is configured.

Dropped Calls After 30 Seconds

Calls connect but disconnect after about 30 seconds.

Solution: Ensure SIP packets can return through your firewall. Enable SIP ALG or use a SIP-aware firewall.

Registration Failures

Trunk shows as "Unavailable" or fails to register.

Solution: Verify credentials, check port 5060 is open, confirm DNS resolution works.

Outbound Caller ID

Configure your outbound caller ID in your PBX:

Format Requirements

  • Caller ID Number: Use one of your IPComms DIDs in E.164 format (e.g., +14045551234)
  • Caller ID Name: Set via CNAM in your portal (15 characters max)
  • P-Asserted-Identity: Optionally include for privacy-aware routing

Note: You can only use phone numbers assigned to your account. Attempts to spoof other numbers will be blocked.

Platform-Specific Guides

Detailed configuration guides for popular PBX platforms:

Testing Your Configuration

1. Verify Registration

Check that your trunk shows as "Registered" in your PBX. You can also verify in the IPComms portal.

2. Test Outbound Calls

Make a call to your mobile phone. Verify you can hear audio in both directions.

3. Test Inbound Calls

Call your IPComms number from an external phone. Verify the call routes correctly.

4. Check Caller ID

Verify your outbound caller ID displays correctly on the receiving phone.

Need Configuration Help?

Our support team can assist with your SIP trunk configuration.