Many ISPs now block external email ports to stem the tide against SPAM. IE, they may block ports 25 and 110 from reaching outside of their network except to from their servers. This may break a person's ability to pick up email from office or school email servers.
No fix is planned since the spammers would take advantage of it.
My daughter is visiting a friend and they have SBC Yahoo DSL connected to SBCYahoo wireless access point/router. She can't access her school's server when she tries to get/sent mail.
Anybody knows how SBC Yahoo sets up their routers?
She has no problems at other places just at the location.