Post Office Protocol

Family of Internet mail protocols Internet protocol suite Application layer BGP DHCP (v6) DNS FTP HTTP (HTTP/3) HTTPS IMAP IPP IRC LDAP MGCP MQTT NNTP NTP OSPF POP PTP ONC/RPC RTP RTSP RIP SIP SMTP SNMP SSH Telnet TLS/SSL XMPP more... Transport layer TCP UDP DCCP SCTP RSVP QUIC more... Internet layer IP v4 v6 ICMP (v6) NDP ECN L4S IGMP IPsec more... Link layer ARP Tunnels PPP MAC more... vte In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. Today, POP version 3 (POP3) is the most commonly used version. Together with IMAP, it is one of the most common protocols for email retrieval. Purpose The Post Office Protocol provides access via an Internet Protocol (IP) network for a user client application to a mailbox (maildrop) maintained on a mail server. The protocol supports list, retrieve and delete operations for messages. POP3 clients connect, retrieve all messages, store them on the client computer, and finally delete them from the server. This design of POP and its procedures was driven by the need of users having only temporary Internet connections, such as dial-up access, al