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popper(8) Maintenance Procedures popper(8)
NNNNAAAAMMMMEEEE
popper - pop 3 server
SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
////uuuussssrrrr////eeeettttcccc////ppppooooppppppppeeeerrrr [ -d ] [ -s ] [ -t trace-file] [ -T timeout]
[ -b bulldir]
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
_P_o_p_p_e_r is an implementation of the Post Office Protocol
server that runs on a variety of Unix computers to manage
electronic mail for Macintosh and MS-DOS computers. The
server was developed at the University of California at
Berkeley and conforms fully to the specifications in RFC
1081 and RFC 1082.
The ----dddd flag sets the socket to debugging and turns on debug-
ging. All debugging information is saved using syslog(8).
The ----tttt ttttrrrraaaacccceeee----ffffiiiilllleeee flag turns on debugging and saves the
trace information in _t_r_a_c_e-_f_i_l_e using fprintf(3V).
The ----ssss flag turns on statistics logging using syslog(8). At
the end of each popper session, the following information is
logged: username, number of messages deleted, number of
bytes deleted, number of message left on server, number of
bytes left on server.
The ----TTTT ttttiiiimmmmeeeeoooouuuutttt option changes the default compiled value
POP_TIMEOUT for terminating a session with a pop client.
When the server is waiting for a command to arrive from the
client, it times out after the specified number of seconds
and terminates the session. This avoids having popper
processes hang forever waiting for command input from
clients which have terminated abnormally. A small value is
ok for small to medium nets where the network delay is
within a few seconds. In this case 15-30 seconds is not
unreasonable. Networks with large delays in sending packets
(e.g., SLIP links) may require a larger value. In this case
300 seconds (5 minutes) is not unreasonable.
The ----bbbb bbbbuuuullllllllddddiiiirrrr option turns on the bulletin feature and
specifies the bulletin directory path.
BBBBUUUULLLLLLLLEEEETTTTIIIINNNNSSSS
The bulletin feature gives system administrators a way to
send important announcements to all POP users without having
to do mass mailings.
The bulletin directory contains one file per bulletin. Each
file contains a single mail message with header and body in
mailbox format. The first line of each such bulletin must be
a "From " line. The easiest way for sysadmins to create such
bulletins is to mail themselves a copy of the bulletin using
Sun Microsystems Last change: August 1990 1
popper(8) Maintenance Procedures popper(8)
the account to which they want replies to be sent, then use
their mail program to save the message to a file in the bul-
letin directory in mailbox format. The bulletin directory
must be world readable.
The name of each bulletin file begins with the bulletin
number, and may optionally continue with any other charac-
ters. E.g., the file name of bulletin number 23 might be
"23.pophost_down_sunday".
Popper creates a file named .popbull in the home directory
of each user. This file contains a single line recording the
highest numbered bulletin received by the user.
Each time a POP client connects to the server, any new bul-
letins which the user has not received previously are
automatically appended to the user's mail.
When a bulletin is copied, the "To" header line is replaced
by "To: username@thishost", and any "Status:" header lines
are deleted. Otherwise, the bulletin is copied as is.
When a new user checks for mail the first time, popper
creates the .popbull file in the user's home directory and
seeds it with the current maximum bulletin number. Thus new
users do not get old bulletins.
TTTTHHHHEEEE PPPPOOOOPPPP TTTTRRRRAAAANNNNSSSSAAAACCCCTTTTIIIIOOOONNNN CCCCYYYYCCCCLLLLEEEE
The Berkeley POP server is a single program (called popper)
that is launched by inetd when it gets a service request on
the POP TCP port. (The official port number specified in
RFC 1081 for POP version 3 is port 110. However, some POP3
clients attempt to contact the server at port 109, the POP
version 2 port. Unless you are running both POP2 and POP3
servers, you can simply define both ports for use by the
POP3 server. This is explained in the installation instruc-
tions later on.) The popper program initializes and veri-
fies that the peer IP address is registered in the local
domain, logging a warning message when a connection is made
to a client whose IP address does not have a canonical name.
For systems using BSD 4.3 bind, it also checks to see if a
cannonical name lookup for the client returns the same peer
IP address, logging a warning message if it does not. The
the server enters the authorization state, during which the
client must correctly identify itself by providing a valid
Unix userid and password on the server's host machine. No
other exchanges are allowed during this state (other than a
request to quit.) If authentication fails, a warning mes-
sage is logged and the session ends. Once the user is iden-
tified, popper changes its user and group ids to match that
of the user and enters the transaction state. The server
makes a temporary copy of the user's maildrop which is used
Sun Microsystems Last change: August 1990 2
popper(8) Maintenance Procedures popper(8)
for all subsequent transactions. These include the bulk of
POP commands to retrieve mail, delete mail, undelete mail,
and so forth. When the client quits, the server enters the
final update state during which the network connection is
terminated and the user's maildrop is updated with the (pos-
sibly) modified temporary maildrop.
LLLLOOOOGGGGGGGGIIIINNNNGGGG
The POP server uses syslog to keep a record of its activi-
ties. On systems with BSD 4.3 syslogging, the server logs
(by default) to the "local0" facility at priority "notice"
for all messages except debugging which is logged at prior-
ity "debug". The default log file is
/usr/spool/mqueue/POPlog. These can be changed, if desired.
On systems with 4.2 syslogging all messages are logged to
the local log file, usually /usr/spool/mqueue/syslog.
DDDDEEEEBBBBUUUUGGGGGGGGIIIINNNNGGGG
The popper program will log debugging information when the
-d parameter is specified after its invocation in the
inetd.conf file. Care should be exercised in using this
option since it generates considerable output in the syslog
file. Alternatively, the "-t <file-name>" option will place
debugging information into file "<file-name>" using fprintf
instead of syslog.
For SunOS version 3.5, the popper program is launched by
inetd from /etc/servers. This file does not allow you to
specify command line arguments. Therefore, if you want to
enable debugging, you can specify a shell script in
/etc/servers to be launched instead of popper and in this
script call popper with the desired arguments.
You can confirm that the POP server is running on Unix by
telneting to port 110 (or 109 if you set it up that way).
For example:
%telnet myhost 110
Trying...
Connected to myhost.berkeley.edu.
Escape character is '^]'.
+OK UCB Pop server (version 1.6) at myhost starting.
quit
Connection closed by foreign host.
EEEEXXXXTTTTEEEENNNNSSSSIIIIOOOONNNNSSSS
The server implements two extended commands.
XTND XMIT: Sends a mail message using /usr/lib/sendmail.
XTND XLIST header [num]: Extracts and returns the specified
header line for the specified message number. If the "num"
Sun Microsystems Last change: August 1990 3
popper(8) Maintenance Procedures popper(8)
parameter is missing, returns the header line for all the
messages which are not currently marked for deletion.
FFFFIIIILLLLEEEESSSS
/usr/spool/mail mail files
/etc/inetd.conf pop program invocation
/etc/syslog.conf logging specifications
~/.popbull largest bulletin number seen by user
SSSSEEEEEEEE AAAALLLLSSSSOOOO
inetd(8), RFC1081, RFC1082
AAAAUUUUTTTTHHHHOOOORRRRSSSS
Bob Campbell, Edward Moy, Austin Shelton, Marshall T Rose,
and cast of thousands at Rand, UDel, UCI, and elsewhere
Sun Microsystems Last change: August 1990 4
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