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We recently added IAS & RADIUS to a 2k3 box over the weekend. The server was rebooted today, and now IAS won't start. Looks like I need to specify some port reservations to get it working.

"netstat -n" does not show any of ports 1645, 1646, 1812, or 1813 in use.

Event log error is:

Event Type: Error
Event Source: Service Control Manager
Event Category: None
Event ID: 7023
Date:  3/14/2011
Time:  4:11:56 AM
User:  N/A
Computer: B90CENT
The Internet Authentication Service service terminated with the following error: 
Only one usage of each socket address (protocol/network address/port) is normally permitted. 

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up vote 1 down vote accepted

I suspect that you're running a DNS server on that machine. The likelihood is that you're seeing the problem described in KB956188.

Add a REG_MULTI_SZ value called "ReservedPorts" at "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters". Add entries to the value for 1645, 1646, 1812, and 1813. Stop and restart the DNS Server service then start the IAS service. You should find that it starts and runs as expected.

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Perfect - it was the DNS server. I'd reserved the ports, but hadn't restarted DNS. Thanks! – jefflunt Mar 15 '11 at 22:20

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