Project Detail

Description

Make a simple POP3 server according to RFC 1939. Server has to be able to process concurrent requests from several clients. POP3 has to support following commands (described as "Minimal POP3 Commands" in RFC 1939): USER, PASS, QUIT, STAT, LIST, RETR, DELE, NOOP, RSET, QUIT.
Authentication of user connecting to the server must work with file named passwd, which has to be saved in the directory where server is running. It must contain user data according to following sample:
user1:pass1
user2:pass2
user3:pass3
Box of each user will be in the same directory and named as a login of its owner (for example user called user1 will have the box named user1).
Box must be in format of mbox (as described in manual pages).

Server usage:
pop3d -p <port>

where -p is optional parameter setting the port which server will be running on. If not entered, server will try to start on port 110.

Sample of communication from client's side:
$ telnet pop3.example.com 110
Trying 12.12.12.12...
Connected to pop3.example.com.
Escape character is '^]'.
+OK Hello, this is POP3 server.
USER user1
+OK Enter your password please.
PASS pass1
+OK 2 3639
LIST
+OK 2 3639
1 2161
2 1478
.
STAT
+OK 2 3639
NOOP
+OK
LIST 1
+OK 1 2161
LIST 2
+OK 2 1478
RETR 2
+OK Message follows (1478 bytes).
Reply-To: =?us-ascii?Q?user2=40example=2Ecom?= <>
Received: (qmail 27468 invoked by uid 0); 27 Sep 2009 16:45:40 -0000
Received: from smtp1.example.com (smtp1.example.com [12.12.12.13])
    by smtp2.example.com (SMTPD 1.1.10@14229) with ESMTP;
    Sun, 27 Sep 2009 18:45:40 +0200 (CEST)
Message-Id: <>
Date: Sun, 27 Sep 2009 18:45:09 +0200 (CEST)
From: =?us-ascii?Q?user2=40example=2Ecom?= <>
User-Agent: Thunderbird 2.0.0.23 (X11/20090817)
Mime-Version: 1.0
To:
Subject: =?us-ascii?Q?Predmet=20emailu?=
Content-Type: text/plain; charset=ISO-8859-2; format=flowed
Content-Transfer-Encoding: 7bit
X-Smtpd: 1.1.10@14229
X-Nod32result: clean (vdv=4442)

This is body of test email.

Email ends after this sentence.
.
DELE 1
+OK Message 1 deleted.
STAT
+OK 1 1478
LIST
+OK 1 1478
2 1478
.
RSET
+OK 2 3639
LIST
+OK 2 3639
1 2161
2 1478
.
STAT
+OK 2 3639
QUIT
+OK Closing connection, see you later.


Try communication with your server by using of standard email clients as well (Mozilla Thunderbird, Outlook...).

Source code must be clean and well commented!


Additional files submitted:
isa.odt