POP (Post Office Protocol)

POP mail is very popular among those who travel with laptops as it allows the user to download emails from a central server and read them locally without after disconnecting. POP mail can offer serious disadvantages when users send large documents. Connection speeds are improving throughout the world although some users still have to access mail via a dial up connection or over a VPN which generally means slower speeds for downloading messages.

POP uses port 110 by default for email transfer and this port must be open to allow email through any firewall that your company may be using.