2talk supports two methods for connecting your 3CX Phone System to our SIP Trunking platform:
(via username/password)
(no registration required)
This guide walks through both options, with a strong focus on (recommended for business-grade setups).
Prerequisites
3CX v18 or later
A valid SIPcity trunk (with either)
Username/Password credentials, or
Whitelisted IP for SIP Peering)
Your outbound public IP must be known and stable (for IP-based peering)
Option 1: SIP Registration (Username & Password)
Use this method if SIPcity has issued credentials.
Trunk Setup
1. Go to SIP Trunks > Add SIP Trunk
2. Choose Generic SIP Trunk
3. Set:
• Registrar: sip.sipcity.com.au or as provided
• Port: 5060 (UDP) or 5061 (TLS)
• Authentication ID / Username: Provided SIP user ID
• Password: Provided password
4. Leave IP-based Authentication disabled
5. Proceed to configure DID routing and codecs
⸻
Option 2: Static IP SIP Peering (No Registration)
Recommended for customers with static IPs.
SIPcity Provisioning
• Your 3CX public IP must be provided to SIPcity and added as a SIP Peering endpoint
• Example:
• Primary Peer IP: 10.10.10.00
• Destination Proxy: 103.55.116.65:5060
3CX Configuration
General Tab
• Registrar/Server: 27.111.12.66
• Port: 5060
• Authentication:
• Select: Do not require – IP based
• Leave Username/Password fields blank
Options Tab
• Transport Protocol: UDP
• SRTP: Disabled
• Re-register Timeout: 0 (⚠️ This prevents 3CX from sending REGISTER packets)
• Public IP in SIP Header: Leave blank unless required
DID Numbers Tab
• Add your SIPcity number(s) exactly as sent (e.g., 13106341786)
• Route each DID to the correct extension or ring group
⸻
Outbound Rule Setup
To match outbound numbers dialled by your users:
Recommended Outbound Rule
Setting | Value |
|---|---|
Prefix | 0,00,13,+ |
Strip Digits | No strip |
Prepend | Leave blank |
Outbound Caller ID | 13106351786 |
Trunk | ip SipCity |
This rule allows local, mobile, international, and E.164 (+61) formatted numbers to route via SIPcity.
Tip: Add a second rule for specific patterns (e.g. international 00 calls) if needed.
⸻
Troubleshooting
Symptom | Likely Cause | Fix |
|---|---|---|
No outbound call | Number does not match an outbound rule | Add or correct dial prefixes |
No SIP INVITE seen on SIPcity | 3CX not matching a route | Create fallback rule with X. prefix |
“No user or outbound rule found” error | Dialed number doesn’t match rule | Review and test dial pattern |
Outbound call fails with 403/404 | Caller ID not valid | Set 61756385444 as Outbound Caller ID |
Inbound calls working, outbound not | SIP trunk is inbound-only | Enable “Allow outbound calls” in trunk |
Firewall & NAT
Ensure outbound firewall rules allow:
• UDP 5060 from your PBX to 103.55.116.65
• RTP Media Range: UDP ports 9000–10999 (as per 3CX RTP settings)
• SIPcity should see your real public IP, not a translated one
Final Checklist
SIPcity has whitelisted your public IP | ✅ |
3CX trunk set to “Do not require – IP based” | ✅ |
Re-register timeout set to 0 | ✅ |
DID added in 3CX exactly as received | ✅ |
Outbound rule matches all formats used by staff |
Summary
While SIPcity is not listed as a certified 3CX SIP trunking provider, we have a large number of 3CX customers connecting successfully via both Registration and Peering:
Detailed connection guides
Support for both and
Proven success with many 3CX-based customers across Australia and the US
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