[X Newbies] MAC OS Reset its Networking?

[Leigh Seaver]

Hi!

I 've been having a problem lately.  I frequently set up my mac for 
overnight file transfer and for several months it has been running 
without a hitch.  Now, recently (say, within the past couple of weeks) 
my internet connection has been terminated during the wee hours of the 
morning with a message that "Mac OS has Reset its Networking".  This 
doesn't happen every night, but perhaps once every three nights or so.  
I find it irritating as I lose several hours of file transfer.

Any ideas on what this is?  Can I change some preference setting to 
stop it?

Thanks,

L