Re: [RadiusNT] Redundancy

Adam Greene ( (no email) )
Mon, 21 Feb 2000 09:35:34 -0500

One option is to run SQL on two servers, do a nightly transfer of the
authentication database from the primary server to the secondary server, and run
a Radius application on both servers. The radius application on server A would
consult the database on server A, and the Radius on server B would consult the
database on server B. That way if the primary server goes down, you have a
fully functioning system to use as a backup.

On the secondary server, you may also wish to enable multiple logins per
customer, because the database on the secondary server is a "point-in-time"
copy. In other words, if someone was online at the time of the database
transfer, the secondary database will continue to register the person as online
even if they subsequently logged off, after the transfer. If you enable
multiple logins on the secondary server, all users will still be able to
authenticate in times of emergency.

Configure your terminal servers to send authentication packets to both your
primary and secondary Radius servers.

I don't suggest database replication because I have heard that it consumes
inordinate server resources.


-----Original Message-----
From: John Sulima <>
To: <>
Date: Sunday, February 20, 2000 4:43 PM
Subject: [RadiusNT] Redundancy

We're a small ISP, but we've been trying to build some redundancy into our
systems. We use a SQL database for our customer records and for authentication
for our Radius and mail server. Even though it's central to our system, I
haven't been able to figure out how to best to create a redundant SQL server.
Does it make sense to replicate the database to another server, perhaps on
another network link? Or should we consider a mirrored server solution? Any
other suggestions?


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