firewall port number for softwareupdate?

wondering if anyone know what port number is the port that apple softwareupdate runs from the GUI? customer has a firewall and the auto softwareupdate is not running. after you enter password and agree to downloads, it tries and errors out. gave a -1057(i think) error. supposedly there is a closed port in the firewall that needs to be opened. manual downloading works, but just not the auto. i have found this Kbase doc:
http://docs.info.apple.com/article.html?artnum=106439

but it doesn't have a cut an dry answer. any help would be appreciated.