Setup Details:
• 3CX Version: Version 20.0 Update 5 (Build 506 Beta)
• Hosting: Google Cloud VM
• Firewall: Google Cloud firewall configured to allow SIP/RTP traffic
• FXO Gateway: Yeastar S20 (located at home)
• Local IP: 192.168.5.218
• Public IP: (My public ip)
• PSTN Line Type: Analog (FXO)
• Authentication Type: IP-based (no username/password)
• SIP Trunk in 3CX: Configured to use Yeastar’s public IP
Issue Description:
I have a 3CX system hosted on Google Cloud, and I am using a Yeastar S20 FXO Gateway at my home to connect an analog PSTN line to 3CX. However, I keep receiving the following Event Log Warning:
• 3CX Version: Version 20.0 Update 5 (Build 506 Beta)
• Hosting: Google Cloud VM
• Firewall: Google Cloud firewall configured to allow SIP/RTP traffic
• FXO Gateway: Yeastar S20 (located at home)
• Local IP: 192.168.5.218
• Public IP: (My public ip)
• PSTN Line Type: Analog (FXO)
• Authentication Type: IP-based (no username/password)
• SIP Trunk in 3CX: Configured to use Yeastar’s public IP
Issue Description:
I have a 3CX system hosted on Google Cloud, and I am using a Yeastar S20 FXO Gateway at my home to connect an analog PSTN line to 3CX. However, I keep receiving the following Event Log Warning:
| Type | Warning |
| Event ID | 30051 |
| Date | 02/03/2025 5:16 PM |
| Details | Unidentified Incoming Call. Review INVITE and adjust source identification: INVITE sip:s@(3cx public ip):5060;transport=udp SIP/2.0 Via: SIP/2.0/UDP 192.168.5.218:5060;rport=5060;branch=z9hG4bKPj186179de-67f6-4046-93a7-caf4560c6f0c;received=(yeastar public ip) Max-Forwards: 70 Contact: <sip:[email protected]:5060> To: <sip:s@(3cx public ip)> From: <sip:Unknown@(3cx public ip)>;tag=fc630785-def9-49f6-b3cb-da0ec33fce24 Call-ID: 95537f4b-d6c5-4d72-acae-efb3dac306b7 CSeq: 26457 INVITE Session-Expires: 1800 Min-SE: 90 Allow: OPTIONS, NOTIFY, SUBSCRIBE, NOTIFY, PUBLISH, INVITE, ACK, BYE, CANCEL, UPDATE, MESSAGE, REFER, REGISTER Content-Type: application/sdp Supported: timer, replaces, norefersub User-Agent: Yeastar S20-30.15.0.179 Diversion: <sip:Unknown@(3cx public ip)> Content-Length: 308 v=0 o=- 864088640 864088640 IN IP4 192.168.5.218 s=Asterisk c=IN IP4 192.168.5.218 t=0 0 m=audio 11536 RTP/AVP 0 8 18 101 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:18 G729/8000 a=fmtp:18 annexb=no a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20 a=maxptime:150 a=sendrecv Upon checking the logs, I can see that the INVITE request is reaching 3CX but is being rejected as an unidentified call. Troubleshooting Done So Far: 1. Whitelisted Yeastar’s Public IP (41.60.189.58) in 3CX Security Settings (IP Blacklist). 2. Ensured 3CX SIP Trunk is set to IP-based authentication (no username/password). 3. Verified Firewall Rules: • Google Cloud allows UDP 5060 (SIP) and UDP 10000-20000 (RTP) from Yeastar’s Public IP. • Home Router forwards SIP/RTP traffic from 192.168.5.218 (Yeastar S20) to 3CX Public IP. 4. Checked SIP Headers in Yeastar S20: • SIP INVITE contains no Caller ID (FXO line does not provide it). • Yeastar S20 is sending sip:[email protected] → <sip:3CX Server>. 5. Set a Default Caller ID in Yeastar S20 to 1000 (to avoid blank Caller ID issues). 6. Enabled “Use Default Number If Missing” in 3CX SIP Trunk Settings. 7. Adjusted SIP Format Settings: • Yeastar S20 now sends P-Asserted-Identity in SIP headers. • Changed Caller ID format to National Format (260XXXXXXXXX). 8. Restarted 3CX and Yeastar S20, but still receiving Event ID 30051. What I Need Help With: 1. How can I make 3CX recognize calls from my Yeastar S20 without rejecting them as “Unidentified”? 2. Is there a way to configure 3CX to accept calls without requiring Caller ID? 3. Should I adjust the SIP headers or change how the INVITE request is formatted? 4. Any additional firewall or SIP trunk settings that might help resolve this issue? Any insights or recommendations would be greatly appreciated! |
