<page_title> List of TCP and UDP port numbers </page_title> <section_title> Well-known ports </section_title> <table> <cell> 110 <col_header> Port </col_header> </cell> <cell> Post Office Protocol, version 3 (POP3) <col_header> Description </col_header> </cell> </table>
A POP3 server listens on well-known port number 110.