All About POP3
Description: All about POP3, the Post Office Protocol

### Using POP3?
Client |  | Windows |  | Macintosh |  | Unix/Linux |
Mail.app |  |  |  | Mac OS 9, 10.x |  |  |
Eudora |  | Win95, Win98, Win2k, WinXP |  | Mac OS 9, 10.x |  |  |
MS Outlook Express |  | Win98, Win2k, WinXP |  | Mac OS 9 |  |  |
MS Entourage |  |  |  | Mac OS X |  |  |
Netscape Mail |  | Win95, Win98, Win2k, WinXP |  | Mac OS 9, 10.x |  | FreeBSD, Linux |
Mozilla |  | Win98, Win2k, WinXP |  | Mac OS 9, 10.x |  | FreeBSD, Linux |
### What is POP3? POP stands for Post Office Protocol. It is a method of accessing electronic mail that is kept on a dedicated mail server. POP3 permits an email "client" program (MUA) to download remote messages to the client computer. POP was designed for "offline" message access and works best when one uses a single computer, wherein messages are downloaded and then deleted from the mail server. This mode of access is not compatible with access from multiple computers since it tends to sprinkle messages across all of the computers used for mail access. Thus, unless all of those machines share a common file system, the offline mode of access that POP was designed to support effectively ties the user to one computer for message storage and manipulation. The protocol includes operations for: checking for new messages; permanently removing messages; setting and clearing flags
### Testing a POP3 account
    [matt@mail] ~ % telnet localhost pop3
    Trying 127.0.0.1...
    Connected to localhost.example.com.
    Escape character is '^]'.
    +OK <74917.1069208003@mail.example.com>
    user matt@example.com
    +OK
    pass secret.words
    +OK
    list
    +OK
    1 20408
    2 122788
    3 4632
    4 16421
    5 3624
    6 3085
    7 2474
    8 3794
    9 3621
    .
    retr 9
    +OK
    Received: (qmail 1737 invoked by uid 1068); 15 Nov 2003 07:58:59 -0000
    Received: from service.buy.com by cadillac.mi.us by with qmail-scanner-1.20rc4
     (clamscan: 0.60.  Clear:RC:0:.
     Processed in 0.029081 secs); 15 Nov 2003 07:58:59 -0000
    Received: from unknown (HELO listserver.buy.com) (209.67.181.22)
      by mac.cdlc.mi.voyager.net with SMTP; 15 Nov 2003 07:58:59 -0000
    Received: from msmq01.msmq.buy.com ([10.10.0.40]) by listserver.buy.com
             Fri, 14 Nov 2003 23:38:06 -0800
    Received: from mail pickup service by msmq01.msmq.buy.com with Microsoft SMTPSVC;
             Fri, 14 Nov 2003 23:46:26 -0800
    From:
    To:
    Subject: Your buy.com Order
    Date: Fri, 14 Nov 2003 23:46:26 -0800
    Message-ID: <088f01c3ab4c$927ebef0$2801020a@msmq.buy.com>
    MIME-Version: 1.0
    Content-Type: text/plain;       charset="iso-8859-1"
    Content-Transfer-Encoding: quoted-printable
    X-OriginalArrivalTime: 15 Nov 2003 07:46:26.0218 (UTC) FILETIME=[929DB8A0:01C3AB4C]
    X-Spam-Status: No, hits=1.3 required=5.0
            tests=NO_REAL_NAME,RCVD_IN_ORBS
            version=2.55
    X-Spam-Level: *
    X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp)

    Hello Matt,

    Thank you for shopping at buy.com.

    *snipped*

    Thank you,

    Team buy.com
    http://www.buy.com

    .
    quit
    +OK
    Connection closed by foreign host.