How to check the Nebula status of uOS firewall on local GUI?

Zyxel_Judy

The Nebula Status tool helps administrators quickly diagnose connectivity issues between their firewall and NCC.

The method:

• Navigate to: Maintenance > Diagnostics > Network Tool > Nebula Status
• Click Test button

When testing Nebula status, the results will indicate whether your firewall can successfully communicate with NCC.

• Green (Success) – The firewall has full cloud connectivity
  
• Red (Failure) – Indicates where the failure occurs in the connection process

1. Phase 1 Failure (No Internet Access)

Error Message: Network is unreachable (8.8.8.8)
Possible Causes & Fixes:

• Check if WAN connectivity is down
  
• Firewall or upstream router may be blocking ICMP (ping)
  

Reminder: Even if Phase 1 fails, your firewall might still be able to connect to NCC, but the test will flag this issue.

2. Phase 2 Failure (DNS Resolution Issue)

Error Message: Cannot resolve d2.nebula.zyxel.com
Possible Causes & Fixes:

• Incorrect DNS settings on the firewall
  
• Blocked DNS queries by upstream security policies
  
• ISP’s DNS server is failing to resolve Nebula’s domain

3. Phase 3 Failure (Nebula Cloud Blocked)

Error Message: TCP ping to d2.nebula.zyxel.com timed out
Possible Causes & Fixes:

• A firewall rule is blocking outbound access to d2.nebula.zyxel.com
  
• ISP or upstream security policy is preventing connection to Nebula