what is this? (sshd messages in log)

[dman <dsh8290@rit.edu>]

I'm sitting at home on the console right now.  I noticed this in
xconsole, copied from /var/log/auth.log :

Jan 24 23:23:50 dman sshd[3760]: Did not receive identification string from 216.153.138.132
Jan 24 23:24:37 dman sshd[3776]: Disconnecting: Corrupted check bytes on input.

It appears that someone is trying to ssh to my machine, but didn't do
it right.  Is this deduction correct?  I looked up that machine and
found :

$ host 216.153.138.12
Name: host-216-153-138-12.choiceone.net
Address: 216.153.138.12

$ nmap 216.153.138.12

(The 1545 ports scanned but not shown below are in state: closed)
Port       State       Service
137/tcp    filtered    netbios-ns              
138/tcp    filtered    netbios-dgm             
139/tcp    filtered    netbios-ssn             
5631/tcp   open        pcanywheredata          


Looks like a windows machine to me.  Is this just a fluke, or is there
some new worm/exploit going around?

Any thoughts, comments?

-D

-- 

"He is no fool who gives up what he cannot keep to gain what he cannot lose."
        --Jim Elliot