Server 2019 Radius blocked by Defender Firewall

Question

_{Friday, January 11, 2019 7:45 PM}

I am having a problem with the Defender Firewall blocking Radius requests.  I have verified the firewall is the problem by turning it off and on.  The radius client is set to use the default ports and the ports are open in the firewall config.  Any ideas?

Steve

All replies (2)

_{Wednesday, May 22, 2019 9:50 PM}

Same here. Turning defender firewall off, enables all communication. Firewall rule for UDP,1812 is green in Advanced Firewall MMC. Something is not good here.

Cheers
Stefan

_{Thursday, April 2, 2020 12:18 AM}

I think this is a bug in Windows Server 2019, but I found two workarounds:

1) Grant the IAS service a higher "security clearance", so that the default rules will match:
sc.exe sidtype IAS unrestricted

2) Modify the built-in firewall rules to work:
Get-NetFirewallRule -DisplayGroup "Network Policy Server" | where DisplayName -like "*RADIUS*" | Set-NetFirewallRule -Service Any

Once done, the rules will more closely match the Windows Server 2016 rules.

I don't know the ramifications of changing security settings on the IAS service, so I recommend simply updating the rules.

Undo actions:

1. sc.exe sidtype IAS none
2. Get-NetFirewallRule -DisplayGroup "Network Policy Server" | where DisplayName -like "*RADIUS*" | Set-NetFirewallRule -Service ias

-Tony