virus def update site?

I have my product (NAV2008) set to check for virus def updates every 3 hours. I notice that

Sometimes it shows updates coming after connecting to

symantec.com

sometimes it shows updates after connecting to

liveupdate.symantecliveupdate.com

 

is that a problem? Or are they just different servers that deliver the same content and it is just random as to which one it connects to??