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- subj: tls049 - POP mail server
-
-
- Useful hints, thanks to: Brian Atkinson:
-
- This is compiled with C2 code. If you dont use C2 it seems to
- break with the message
- Security command was invoked without ANY arguments
-
- I altered popper.c and pop_pass.c so that where C2 was required, I had
- #if defined(SCO) && defined(C2)
- which cured the problem.
-
- Further to this, there are some funnies when sending a mail
- Attempting a reply (xtnd xmit) seems to give you the message
- No valid author present
-
- This is from sendmail, *not* popper. I'm not entirely sure what is
- causing this as it may be package related or the use of the sendmail
- flags within popper itself. However, many "pop" packages seem to use
- pop to pick up but then can use SMTP to send. I've simply configured
- our pop packages (B&W, QVTnet amongst others) to send with SMTP. I'll
- be honest and say I didnt spend any time worrying about it. I just
- switched to SMTP and forgot it.
-
- However, it *does* work (after the C2 removal) and seems to be very reliable.
-
- brian
-
- -----------------------------
-
-
- From the README file:
-
- Introduction
-
- The Post Office Protocol server runs on a variety of Unix[1] 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[2] and RFC 1082[3].
- The Berkeley server also has extensions to send electronic mail on
- behalf of a client.
-
- Contents of the Distribution
-
- The distribution contains the following:
-
- + All of the C source necessary to create the server program.
-
- + A visual representation of how the POP system works.
-
- + Reprints of RFC 1081 and RFC 1082.
-
- + A HyperCard stack POP client implementation using MacTCP.
-
- + A man page for the popper daemon.
-
- + This guide.
-
-
- Compatibility
-
- The Berkeley POP server has been successfully tested on the following
- Unix operating systems:
-
- + Berkeley Systems Distribution 4.3
-
- + Sun Microsystems Operating System versions 3.5 and 4.0
-
- + Ultrix version 2.3
-
- [ SCO UNIX version 4.2 ]
-
- The following POP clients operate correctly with the Berkeley POP server:
-
- + The Berkeley HyperMail HyperCard stack for the Apple Macintosh
- (distributed with the server).
-
- + The Stanford University Macintosh Internet Protocol MacMH program.
-
- + The Stanford University Personal Computer Internet Protocol MH
- program.
-
- + The mh version 6.0 programs for Unix.
-
-
- Support
-
- The Berkeley POP server is not officially supported and is without any
- warranty, explicit or implied. However, we are interested in your
- experiences using the server. Bugs, comments and suggestions should be
- sent electronically to netinfo@garnet.Berkeley.EDU.
-
-
- Operational Characteristics
-
- The POP Transaction Cycle
-
- 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 instructions later on.)
- The popper program initializes and verifies 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 message is logged and the session ends. Once the user is
- identified, 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 (ordinarily in /usr/spool/mail) which is
- used for all subsequent transactions. These include the bulk of POP
- commands to retrieve mail, delete mail, undelete mail, and so forth. A
- Berkeley extension also allows the user to submit a mail parcel to the
- server who mails it using the sendmail program (this extension is
- supported in the HyperMail client distributed with the server). 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 (possibly) modified temporary maildrop.
-
-
- Logging
-
- The POP server uses syslog to keep a record of its activities. 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 priority "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.
-
- Problems
-
- If the filesystem which holds the /usr/spool/mail fills up users will
- experience difficulties. The filesystem must have enough space to hold
- (approximately) two copies of the largest mail box. Popper (v1.81 and
- above) is designed to be robust in the face of this problem, but you may
- end up with a situation where some of the user's mail is in
-
- /usr/spool/mail/.userid.pop
-
- and some of the mail is in
-
- /usr/spool/mail/userid
-
- If this happens the System Administrator should clear enough disk space
- so that the filesystem has at least as much free disk as both mailboxes
- hold and probably a little more. Then the user should initiate a POP
- session, and do nothing but quit. If the POP session ends without an
- error the user can then use POP or another mail program to clean up his/her
- mailbox.
-
- Alternatively, the System Administrator can combine the two files (but
- popper will do this for you if there is enough disk space).
-
-
- Debugging
-
- 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. (To enable debugging, you must edit the Makefile
- to add -DDEBUG to the compiler options.)
-
- 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.
-
- Limitations
-
- + The POP server copies the user's entire maildrop to /tmp and
- then operates on that copy. If the maildrop is particularly
- large, or inadequate space is available in /tmp, then the
- server will refuse to continue and terminate the connection.
-
- + Simultaneous modification of a single maildrop can result in
- confusing results. For example, manipulating messages in a
- maildrop using the Unix /usr/ucb/mail command while a copy of
- it is being processed by the POP server can cause the changes
- made by one program to be lost when the other terminates. This
- problem is being worked on and will be fixed in a later
- release.
-
-
- Credits
-
- The POP server was written by Edward Moy and Austin Shelton with
- contributions from Robert Campbell (U.C. Berkeley) and Viktor Dukhovni
- (Princeton University). Edward Moy wrote the HyperMail stack and drew
- the POP operation diagram. This installation guide was written by
- Austin Shelton.
-
-
- Footnotes
-
- [1] Copyright (c) 1990 Regents of the University of California.
- All rights reserved. The Berkeley software License Agreement
- specifies the terms and conditions for redistribution. Unix is
- a registered trademark of AT&T corporation. HyperCard and
- Macintosh are registered trademarks of Apple Corporation.
-
- [2] M. Rose, Post Office Protocol - Version 3. RFC 1081, NIC,
- November 1988.
-
- [3] M. Rose, Post Office Protocol - Version 3 Extended Service
- Offerings. RFC 1082, NIC, November 1988.
-