Contents
Forwarding and "mailhome"	Reading mail locally	Reading remotely (POP and IMAP)
Mail relaying	JILA Webmail	Spam and virus filtering
Vacation autoreply	Reading mail securely

Forwarding and CU's "mailhome" system
Many people want all of their incoming email messages, regardless of the address to which they were sent, to arrive on a single mail server. On Unix systems at CU, this can be accomplished via .forward files, aliases, and the "mailhome" system.

mailhome redirects messages inbound to @colorado.edu addresses or to campus hosts such as spot. Your mailhome can be any mail server in the world and is set when you first receive an account on a Unix system anywhere within CU. For example, if Jane Smith's mailhome is jilau1.colorado.edu and her username is smithj, then messages sent to Jane.Smith@colorado.edu will be directed to smithj@jilau1.colorado.edu. To change your mailhome, send an email to unix@jila.colorado.edu.

The mail servers in JILA do not participate in the mailhome system, so if a user's mailhome is spot, messages sent to user@jilau1 won't be redirected to user@spot. However, by creating a file named .forward in your home directory on a Unix machine and putting an email address in it, you can have incoming messages sent on to that address. For example, if your .forward file on jilau1 contains the line "your_username@gmail.com", any messages that you would have received on jilau1 will be forwarded instead to your gmail account. To keep a copy of each email on the local system as well as forwarding it to another address, put a line like this in your .forward file:

      \local_username, username@remote.system.edu

An email alias on a mail server allows messages for a given username to be forwarded even if the username doesn't correspond to a real account on the server. If you are leaving JILA and still want messages sent to jilau1 to reach you, contact unix@jila.colorado.edu about setting up an alias to your new address.

Be aware that .forward files, aliases, and mailhome can interact in such a way as to create mail delivery loops. It would be bad to have your mailhome set to jilau1 and a .forward file on jilau1 pointing to your account on spot; in this case a message sent to spot would be redirected to jilau1 which in turn would forward it to spot, and so on.

Reading mail locally
If you are logged directly in to a mail server, you can read your email using a terminal-based program such as mail or pine. pine is fairly simple and intuitive and is the most widely used local mail reader. It also has the advantage of using mail folder formats that are compatible with most other mail readers, so you can switch between it and a mail client that you may be using for reading messages remotely. Just type "pine" on the command line to start it up. Introductory documentation is at www.washington.edu/pine.

Reading mail remotely with POP or IMAP
If you prefer to read email using a client program (such as Outlook, Eudora, or Thunderbird) on your desktop or laptop, you can access your messages from the mail server using either the POP or IMAP protocols. jilau1 and most of the distributed mail servers in JILA support POP and IMAP.

POP (Post Office Protocol, also called POP3), downloads messages from the mail server to your local machine, where you can read them, store them in folders, etc. The advantage of POP is that once you have downloaded your mail, you no longer need to be on a network in order to read the messages. The downside is that once the messages are on your local computer, they are no longer accessible from another computer (eg, a home system or laptop.)

IMAP (Internet Message Access Protocol, also called IMAP4), allows you to read and manipulate messages on a remote mail server. Its main advantage is that you can see your mail and any mail folders you have set up from any computer that has an IMAP client program on it. However, in most cases it's necessary to be connected to a network in order to access your messages.

Reading mail remotely with JILA Webmail
JILA offers secure webmail which can be accessed from any browser. For instructions, see this page.

Relaying mail through jilau1
In order to send email from a client program on a computer that isn't the mail server, you need to configure the client to use an "SMTP server" or outgoing mail server. However, in order to avoid being abused by spammers, most SMTP servers will only allow computers within their own domain to send, or relay, email through them. If your computer is in the colorado.edu domain, then you can use jilau1 directly as an SMTP server. If you want to send mail from your home system via your cable modem, or from your laptop when travelling, you can still relay messages through jilau1 after authenticating.

The details of setting up a mail client to use authenticated SMTP vary between programs, but in general you will want to configure your client to "send username and password for SMTP" or "authenticate to SMTP server". In addition, choose TLS (or "TLS, if available") as the secure connection method. Once this is set up, you will be prompted for your jilau1 username and password each time you send a message; once you provide these, jilau1 will relay your outbound mail.

If you find the authentication process too cumbersome, you can still relay through jilau1 from anywhere in the world by making your computer appear to be within the colorado.edu domain. The easiest way to do so is with a Virtual Private Network connection; see vpn.colorado.edu for details about CU's VPN application.

Spam and virus filtering
Unfortunately, a large fraction of today's email carries some sort of malicious payload (a virus, trojan, or worm), unsolicited commercial content ("spam"), or an attempt to get the recipient to divulge private information ("phishing" attacks.) You should never respond to a spam message, always delete (without opening) messages with suspicious attachments, and always get independent verification before responding for a request for personal information.

jilau1 provides several means of reducing the number of spam and virus messages that reach your inbox.

Virus filtering. jilau1 quarantines any incoming message containing an attachment with a filetype extension frequently used by viruses. These include .bat, .scr, and .pif. In addition, jilau1 renames attachments with other potentially problematic extensions (including .zip, .com, and .exe) so that the attachment can't be automatically run by a mail client.

Messages containing known virus signatures are also quarantined, although the list of signatures is not necessarily very complete or up-to-date.

Spam filtering. On jilau1, you can enable the SpamAssassin program, which is very effective at identifying and tagging incoming spam messages. To do so, create a file called .procmailrc in your home directory; it should contain the following lines

   PATH=/usr/bin:/usr/local/bin    
   MAILDIR=$HOME/mail              
   VERBOSE=no                      
   COMSAT=no                       
   SENDMAIL=/usr/sbin/sendmail     
   :0fw: spamassassin.lock
   * < 256000
   | /usr/local/spamassassin/bin/spamc
   #:0:
   #* ^X-Spam-Status: Yes
   #CaughtSpam         

SpamAssassin is highly customizable. To set up a personal configuration, create a directory called .spamassassin in your home directory and in it make a file called user_prefs. Here is a sample of some of the customizations that can go in user_prefs.

One of SpamAssassin's most potent features is its ability to use a Bayesian algorithm to learn to identify which messages you personally consider to be spam or nonspam. To set up Bayes filtering, create a user_prefs file per the example above, with the "use_bayes" option set to 1. To train SpamAssassin to recognize spam messages that you have saved in a mail folder called SpamLearn, run the following command:

   /usr/local/spamassassin/bin/sa-learn --mbox --spam ~/mail/SpamLearn

   /usr/local/spamassassin/bin/sa-learn --mbox --ham ~/mail/NotSpam

Vacation autoreply
If you will be unable to check your email for a period of time, it's useful to send an automatic response to anyone who has sent you a message. Unix provides the vacation program to handle automated responses. However, vacation is not very user-friendly, so at JILA you can use two front-end programs called onvacation and offvacation to set up an autoreply.

When you run onvacation at the command line on jilau1, you'll be placed in a text editor session in which you can customize your autoreply message. Type Control-X to exit the editor (answering yes to any prompts.) When you are returned to the command line, the vacation program will be active. To disable the autoreply, just run offvacation at the command line.

Reading mail securely
Plain POP and IMAP send your username and password in clear text when you log in to access your mail. Thus for security reasons jilau1 will only allow POP and IMAP connections from outside of JILA that are encrypted using SSL. Instructions for setting up your mail client to use SSL can be found here. Even if you are reading mail from within JILA, we still recommend using encryption to help ensure the integrity of your account and privacy of your communications.