SIPcity 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
⸻
Step 2: Static IP SIP Peering (No Registration)
Recommended for customers with static IPs.
How to configure
Log into your SIPcity account
Navigate to Switchboard
Select your main Peering phone number
Go to Preferences
Locate SIP Peering Global Enabling Peering
Enter your Primary IP address (Optionally enter a Failover IP address)
Select Save
Step 3: Configure the SIP Trunk in 3CX
Step 1 – Create the SIP Trunk
Log in to the 3CX Management Console
Go to SIP Trunks
Select Add SIP Trunk
Choose Generic SIP Trunk
General Tab
Setting | Value |
|---|---|
Registrar / Server | 103.55.116.65 |
Port | 5060 |
Authentication | Leave blank |
UserName | Leave blank |
Password | Leave Blank |
Options Tab
Setting | Value |
|---|---|
Transport Protocol | UDP |
SRTP | Disabled |
Re-register Timeout | 0 |
Public IP in sip header | Leave blank |
DID Numbers Tab
Add the SIPcity numbers exactly as issued.
Example format: 6125638544
Each DID should then be routed to the appropriate extension, ring group, or IVR within 3CX.
Network requirements
Setting | Value |
|---|---|
SIP | UDP - 103.55.116.65 |
RTP | UDP 10-20,000 |
⸻
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 | 61756385444 |
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