I've been reading just about anything and everything I can find about 10053 error, since I encountered this error 27 hours ago, and I have yet to fix the problem.
In my case, this is how it shows:

[15:39] * Connect retry #1 irc.rizon.net (6666)
[15:39] -irc.rizon.net- *** Looking up your hostname...
[15:39] -irc.rizon.net- *** Checking Ident
[15:39] -irc.rizon.net- *** Couldn't look up your hostname
[15:48] * [10053] Software caused connection abort
[15:48] * Disconnected
[15:48] * Connect retry #2 irc.rizon.net (6662)
[15:51] * [10053] Software caused connection abort
[15:51] * Disconnected

There are two oddities I noticed.
1. Normally, after showing "Couldn't look up your hostname" message, it procedes to check IP address, then connection establishes. However, it hasn't done that since this error occured.
2. There is abnormally long delay (or generally slow) during the connection attempts. It took 12 minutes to try connecting twice, and I found it strange, since it rarely takes more than 2 minutes to connect.

Here are my connection:
Windows XP Professional SP1
.edu T1 connection
mIRC 6.14 with SysReset 2.53

I have tried to use different IRC programs including UPP, and xchat, with same result. Along the line, I heard a rumor about IT having ability to block IRC from school net, but it does not seem likely. I am leaning towards server equipment failure, or error due to attack, but I cannot be sure.

Can someone help me? I read the common cause/solution, and it doesn't seem to fix the issue. And I am also bothered by "Couldn't look up your hostname" line. Any suggestion?