While doing some testing with Cisco Access Registrar (CAR) 5.0, I noticed that the test user had hundreds of old sessions hanging around:

--> query-sessions /r with-User X
Sessions with-User X for /Radius
  Sessions for /Radius/SessionManagers/session-mgr-1:
    S432 Key: 04000000000CF660, NAS: NAS.slaptijack.com, NAS-Port: 0, User-Name: X, Time: 21:19:26, Acct-Session-Id: 04000000000CF660
<snipped a lot of lines>

--> count-sessions /r with-User X

Total 469 session(s) with-User X for /Radius/SessionManagers

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>>> print "".join(" hello   world ".split())
helloworld

The key to the above is that the String method split() separates the string on any amount of whitespace when no separator is specified.

Interesting technology-related news from around the web for 2010-08-31:

• Recover Data Like a Forensics Expert Using an Ubuntu Live CD – How-To Geek
• 10 ways your Mac can make you smarter | News | TechRadar UK
  'Nuff said!
• The Silent Number: Ubuntu 10.04 Post-Install Guide: What to do and try after installing Lucid Lynx!

Interesting technology-related news from around the web for 2010-08-30:

• Linux Newbie Guide: Shortcuts And Commands
  This is useful for my less Linux-savvy friends.
• Removing an object on a photo with GIMP
  Really useful if you need to doctor some images.
• Engineering Firm Moves Away From VMware | Geek Run Virtualization Blog
  Engineering firm CH2M Hill recently began moving away from VMware ESX to Microsoft’s Hyper-V.

In a test lab, we ran into a situation where the connection between our Cisco Access Registrar (AAA) server and MySQL server was timing out. This forced the server to reconnect and resulted in the following errors:

 name/radius/1 Error Server 0 ODBC client (DataSource 'my_odbc', Connection 8): SQLExecute failed: SQLState:08S01 NativeError:2006 ErrorText:[MySQL][ODBC 3.51 Driver][mysqld-5.0.21-log] MySQL server has gone away
name/radius/1 Error Server 0 Service odbc has no active remote servers available

Obviously, the MySQL server was still there, but after the wait_timeout expires, the server severs the idle connections. By default, the wait_timeout is set to 8 hours. This is obviously much longer than is usually necessary, but in our test lab, it caused problems every morning.

The fix is to set the KeepAliveTimerInterval in the Remote Servers configuration in Cisco Access Registrar. The value defaults to 0, which means no keep-alives are sent. When you set this value, remember that it is in milliseconds. If you forget, you are going to be send lots and lots of keep-alives to your database server!