multiple webserver visits by unidentified robot

[Grace Garbe]

My webserver logs show that an unidentified robot visited my server on 24 April and  requested the robots.txt file a total of 24 times within a twelve hour period.  The requests began at approximately 1:00 am and were repeated every thirty mintues for the next 12 hours.  I have tried to find out to whom the IP address is registered (209.67.247.153) using UNIX nslookup and using D. Richard Dowdy's Internet Address Utility  (http://www.world-net.net/cgi/rdowdy/netutil).  Neither utility can ID this address.  I am able to ping it and that's all.

I have 3 questions:
1.  Why would a robot exhibit this kind of activity?
2.  Does anyone recognize this IP address?
3.  I am going to edit my robots.txt file to attempt to exclude this robot.  Can that be done just by using the IP address since I don't know the robots name?

Thanks in advance for your help.

Grace Garbe
Systems Librarian/Webmaster
Acker Library
DSMC
Ft. Belvoir, VA

garbe_grace at dsmc.dsm.mil