Issue
Zero Config that is unable to auto-detect different subnets. Error “LAN port is disconnected. Please connect LAN port to discover again” pops up each time running the scan
Scenario or System Info
System Info: UCM6510 1.0.20.43
IP Range: UCM IP: 172.26.28.250 GAC2500: 192.168.20.101
Troubleshooting steps
– UCM62XX can ping GAC2500
– GAC2500 can access UCM62XX.
– Manual registration works-
– Verify Fortinet has all ports open
- Verify UCM’s LAN port is connected
– Verify there is no NAT configured in the phones or extensions.
Workaround
a. Make sure that the UCM is in Switch Mode under Network Setting
b. Connect the cable to the WAN port
c. Power up the UCM using PSU
d. Auto discover works
Cause:
This is a known issue in UCM62XX and UCM6510. Unlike UCM63XX, in UCM62XX/6510 WAN and LAN ports are identified. When you plug in a cable to UCM62XX’s LAN port and it discovers external devices (from different subnets), UCM will detect them via the WAN port, so causing the error.
Auto Discover behavior
1. When the subnets are too large, UCM takes time to scan and search the IP Phones.
2. If the IP phone is directly located in the same subnet as the UCM, the IP phone usually has the 3CX option enabled by default.
As long as the IP phone and the UCM are powered on, the IP phone can be discovered through the SIP protocol.
However, if the IP phone is in a subnet within the UCM subnet, it cannot be discovered.
3. It is recommended to divide the subnets into /24. This way, you can perform broadcast searches relatively quickly (by adding subnet whitelisting in Zero Config).