Rather than just ignore your post, I figured that at least some sort of reply would let you know that someone did actually read it. I have not seen this problem before. I assume there is nothing in the startup items that would initiate this connection attempt?
Please let us know if you found an answer elsewhere.
I have a G4 iBook with 768 meg of ram running Tiger OS X (10.4.2) as part of a mixed Mac PC network. Mac mini with OS X Tiger (10.4.2) with 256 meg of ram which is the web server for my web site and blog. An ancient IBM Aptiva with a 500 MHz Athlon chip and 768 meg of ram. All work well together. Recently, within the last week, I get a pop-up after logging in to the iBook which attempts to connect to the server (that is the mini which is serving my web site). The option is to login as a registered user or a guest. This is the same process I would normally use to connect to any other computer on the network but this happens automatically each time I logon to the iBook. I think it has something to do with an nfs connection but I don't recall ever doing anything to set this up. I have the option to cancel the process which leaves everthing as I normally expect them to be. I recently updated to Tiger but this 'activity' did not happen until I had been using Tiger for at least a week. Any suggestions?