Mail Client Configuration

The CS department mail server is mail.cs.byu.edu. It supports both pop and imap. SSL and TLS are supported and required. You must use SSL or TLS (both secure ways of connecting) to connect to the department mail server. This is true for both incoming and outgoing mail.

All mail configurations should point to the server: mail.cs.byu.edu.

You can choose how to configure your mail client based on your preferences. pop3 and imap are for checking your mail. smtp is for sending mail (outgoing). The s at the end of the protocols indicates it'll use SSL for secure connection.

Mail Clients

Below are several clients that can be used to check your email. We don't officially support these applications on the CS Department computers, so if you have a problem we might not be available to help you. There is quite a bit of documentation on the Internet that can help you should you have any trouble. Try http://www.google.com/ if you have any questions.

mutt -f ~/.maildir -m maildir

Forwarding Email

You can have email to your CS Department address forwarded to another address. We have set up a web interface for you to configure this forwarding. It can be accessed through http://accounts.cs.byu.edu/.

The web interface simply creates a file in your home directory (the F: drive on Windows) called .forward containing the address you want your email forwarded to. You have more flexibility with email forwarding if you edit this file yourself. For example, you can have your email forwarded to multiple accounts, just put one email address per line. If I want my mail to be forwarded to my two other e-mail addresses, my .forward file should look like this:

myfakeaddress@hotmail.com
asdf12@email.byu.edu

What is Procmail?

Procmail is a very popular automatic mail processor. You can create a set of filters to process your email before it goes into your mailbox. This means you can have e-mail from different people or mailing lists automatically go to different folders, or block someone all together. Procmail can do a lot, but can also get very complicated. We aren't Procmail tech support, but the following config file should start you in the right direction. There are many sites on the Internet that can give you a more detailed explanation.

To use Procmail, create a file called .procmailrc in your home directory. The following .procmailrc file should be a good template.

###############################################################
# Log file (this log file is a lot of help)
# You'll probably want to comment this out once everything
# is working

LOGFILE=$HOME/.maillog

# Set on when debugging
# Comment this out too after everything is set up
# or set VERBOSE=no  VERBOSE=yes
# Filters:
# BYU Unix Users Group Mailing List
# Search for the string uug-discuss@clubs.byu.edu in
# the Reply-To field; if a message matches it put it
# in my mail/uug-messages folder

:0:
*^Reply-To.*uug-discuss@clubs.byu.edu
$HOME/mail/uug-messages

# Bugtraq Mailing list
# For this list I check for the list address in the To and
# CC fields

:0:
*^To.*bugtraq@securityfocus.com
$HOME/mail/security-messages

:0:
*^Cc.*bugtraq@securityfocus.com
$HOME/mail/security-messages

# In this case I'm looking for anything that has [admincvs] in
# the Subject field

:0:
*^Subject.*\[admincvs\]*
$HOME/mail/CVS
###############################################################

Vacation Auto-responder

These are procmail rules that can respond to e-mails when you are on vacation. They are slightly modified versions of the rules found here http://www.maths.ox.ac.uk/help/faqs/communication/filtering. The first rule simply adds the e-mail address to a list (~/.vacation.cache) the first time it sees an e-mail from that particular address. This is so that consecutive e-mails from the same address won't receive additional auto-responses. The procmail matching patterns are there to try to weed out mail from mailing lists, and anything that could possibly cause an infinite mail loop.

The second rule is what actually sends out the auto-response. It generates the mail headers based on the incoming message, and slaps in a message body that you specify by creating the ~/.vacation.msg file and putting the text that you want in it.

:0 Whc: $HOME/.vacation.lock
* $^(To:.*$LOGNAME|CC:.*$LOGNAME)
* !^FROM_DAEMON
* !^List-
* !^(Mailing-List|Approved-By|BestServHost|Resent-(Message-ID|Sender)):
* !^Sender: (.*-errors@|owner-)
* !^X-[^:]*-List:
* !^X-(Authentication-Warning|Loop|Sent-To|(Listprocessor|Mailman)-Version):
* !$^From +$LOGNAME(@| |$)
| /usr/bin/formail -rD 8192 $HOME/.vacation.cache

:0 ehc
| (/usr/bin/formail -rI"Precedence: junk" \
 -A"X-Loop: $LOGNAME@cs.byu.edu" ; \
 cat $HOME/.vacation.msg ) | /usr/sbin/sendmail -t

When you are back from vacation, delete or comment out these rules, and remove your ~/vacation.cache file.

When I looked at these rules, I wanted to know what they were doing with my mail. The first rule's flags: Whc make it run the command, but not eat the message. The W and c is what really matters. W means wait on this process-- the next rule depends on this rule to have finished outputting what it needs to in the vacation.cache file. The c tells it to continue on to the next rule with the text of the message in tact. It doesn't use the output of this command as the text of the message as it traverses the rest of the rules.

The next rules does the same thing with the c. The command it pipes the message to actually generates and sends the message. It doesn't have a W, so it will take care of that in the background while procmail traverses the rest of the rules.

You should put this below your spam filtering rules, and above any rules that don't continue if the message matches. Of course, you could put rules relating to the sorting of mailing lists above this rule, to have double insurance that the vacation auto responder won't be processing and responding to mailing lists.

Preventing spam

The most important ways you can stop spam are by not sending it and not supporting it. Do not forward email to people to whom it does not directly pertain. Do not use the email address of people whom you don't know. Never respond to spam. Don't buy from companies that send spam. Tell companies that spam will hurt their reputation and cause them to have fewer customers.

By being careful with your email address you can prevent spam from occurring. Think carefully before giving your email address away--especially when entering an online form. Many companies sell customer's information to spammers and direct marketers. It is often helpful to have a junk email account that you can use in any online form, and which you can replace whenever it starts getting too much spam.

Most email clients will filter your email to prevent you from receiving unwanted messages. There are three methods of disposing of unwanted email: trashing, marking, and bouncing. Trashing is when the mail client simply discards the unwanted email into the trash folder, or deletes it. Marking is when the email client marks spam and puts it in its own folder so that the user can then throw away the stuff that he or she does not want. Bouncing is when the email client feigns that the address does not exist and sends back all suspected spam as undeliverable. Many bulk emailers automatically drop bounced email from their lists.

Most email clients provide a way to filter spam using one of the above methods. You should check the documentation of your preferred email client to see what spam filtering functionality it provides.

Filtering Spam

SpamAssassin (http://spamassassin.org) is run on the department mail server. If you examine the headers of an incoming message, you can see it at work. You can then use procmail to filter the junk email into your trash folder, or to delete it immediately by sending it to /dev/null.

A sample procmailrc to automatically delete high scoring SpamAssassin marked messages:

:0:
* ^X-Spam-Level: \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*
/dev/null

A sample procmailrc to filter SpamAssassin marked messages is:

:0:
* ^X-Spam-Status: Yes
.maildir/.Junk/

Please note that if you want to use both rules, you need to have the first rule located higher in your .procmailrc file. If you have the rules swapped, procmail will match the offending message with the first rule, and move it to your junk directory.

What to do when you are blacklisted

A blacklist is a list of IP addresses which have been used by spammers, and so should not be trusted to give good email. Blacklists are maintained by private organizations and are populated according to the maintainer's policies. In an effort to encourage ISPs to secure their mail servers and not allow spammers, some blacklist maintainers choose not only to block the offending IP address, but to also block all address on the same network. This makes all the customers of that Internet Service Provider angry, and hopefully forces the ISP to secure its mailserver and stop supporting spam.

Whether or not you agree with the method of the blacklist maintainers, the only way an IP address can get removed is by securing the offending mail server. This might involve you complaining to your ISP, or changing ISPs. You can also negotiate with the intended recipients of your email to get them to ignore the blacklist on which your IP address is listed.

Newsgroups

Programs such as Netscape and Mozilla Mail, Sylpheed, Pine, Mutt, and Emacs Gnus will let you browse newsgroups and post messages. However, if your class uses Blackboard, we regret to inform you that you have little hope for using a useful newsgroup client. Blackboard discussion groups require that you use Blackboard to read or post messages to the discussion groups (at least at the time this document was written).

We are not in charge of anything related to blackboard, class discussion groups or your RouteY account. If you have problems call the Office of Information Technology at 378-4000.