Mail in the Computer Laboratory

Mail addresses

Users in the department have three options of University mail address to publish:

• user@hermes.cam.ac.uk — using a mailer provided by the Computing Service, which is typically accessed by an IMAP4 mail reader, or through a web-mail interface; Hermes accounts are in principle available to any member of the University (students usually have one set up when they first arrive).
• user@cl.cam.ac.uk — using mailers provided by the Laboratory, which delivers locally, and may be accessed by mail readers tailored for local storage; such accounts are available to staff, visitors and research students
• user@cam.ac.uk — using mail router provided by the Computing Service that can only forward your mail to some other service; ‘accounts’ are available to all members of the university, and you manage them using a Raven-protected database access page.

The laboratory requires that everyone (with a computer account or an office here) be readily accessible via email.

Users’ Lab accounts are allocated two forms of address, by default. For example a user Giles Murchison, whose Computing Service CRSid is gsm10 would have email addresses

gsm10@cl.cam.ac.uk, and
Giles.Murchison@cl.cam.ac.uk

The mail system typically re-writes all mail addresses into the latter (full name) form, unless the user is a taught-course student: see below).

Note: It is possible that the automatic processor that generates these full name addresses will make a mistake (for example, if you don’t habitually use your first name but one of your other fornames). This can be corrected: see section “Problem resolution”, below.

A Lab address is allocated before the user arrives in Cambridge.

Types of address

In practice, whether they have an account at the Lab or not, everyone associated with the Lab has an address here. There are different categories of such addresses:

• If the user is a student on a ‘taught’ course (currently, any part of the Tripos and the ACS MPhil), the address is merely a “stub” pointing at the student’s “@cam” address. These stub addresses are automatically generated and the student has no control over them.
• If the user is a member of academic staff, local delivery to the address is under the user’s control. The email address is usually set up to forward to the user’s previous address, using a .forward file.
• If the user is a member of assistant staff, the email address is set up to forward to the user’s mailbox on the Lab’s MicroSoft Exchange server.
• If the user is a visitor, the email address is set up to forward to an address supplied by the visitor’s host, using a .forward file; again, this forwarding remains under the control of the user.

Special mail addresses

The Lab maintains a number of “rôle addresses”, with which you can get to the right person quickly, for an enquiry. Browse the list of all such names — it’s unlikely you’ll ever need more than one or two of them on a regular basis.

The Lab also runs a simple mail list system; Lab mail addresses with hyphens in them will typically be addresses of lists. See “managing mail lists” for details.

The Admin lists

The department maintains two “extra-special” addresses, with lists of (more or less) everyone attached. These addresses are:

building-users@cl.cam.ac.uk, which gets to everyone in the building. Building-users will be used to send significant building notices, like closures, possible obstructions, work going on in the building, etc.

teaching-research@cl.cam.ac.uk, which gets to all Laboratory Staff and Research Students, but not those in other institutions in the building. Teaching-research will be used for notices about seminars, hints about possible grants/prizes, changes to Laboratory systems, etc.

In both cases, the lists are moderated; please mail postmaster, separately, to alert the team to the presence of the message. (Adding postmaster to the addressees of the message (for example, as Cc:) will not work; the copy will also be “frozen for moderation”.)

Mail that doesn’t fit with broad outlines above will be rejected, as will replies to mail on the list.

A further problem arises with attachments: a mailing list is a terrible way to distribute a document (a copy ends up in everyone’s mailbox). Please make the message a simple plain text object (no html, no attachments); if you want to send something more, put it on the web and include a link to the document in your message.

Mail readers

Lab system mail readers

The Lab’s Unix mail system is configured to support the mh family of mail readers (“MUAs”). Supported instances of mh are:

• mh itself, a collection of small command-line utilities each of which does a simple job (such as compose and send a message (comp), incorporate newly-delivered mail (inc), read the current message (show), etc. For details of the full set, try man nmh and follow up the component programs, again using man
• exmh is a graphical front-end to the mh collection. While simple use is pretty intuitive, there is comprehensive help available from within the program itself.
• The emacs package mh-e is an alternative front-end to the mh collection. Like most emacs packages, it’s comprehensive, occasionally infuriating, and documented using the GNU info system.

Beware of other options that seem superficially capable of using mail delivered into a ~/.mail file: file locking is vital, and some programs will not interwork with the Lab’s file locking, which may lead to loss of mail. Consult systems administrators before trying any such mail reader.

Note that the old “mail” program is not supported.

Hermes mail readers

Many users of Hermes will use the Computing Service’s Web mail system; this is a highly efficient service, and will appeal to most who like that sort of service…

Most (if not all) Linux distributions offer the text-based pine mail reader, which may be used for access to Hermes; visually-based mail readers are available in abundance: consult the Computing service advice on settings before proceeding.

Mail delivery

Lab mail is ordinarily delivered, in MMDF format, to a file .mail in your home directory. The mh-related programs expand .mail into subdirectories of Mail/ in your home directory (principally Mail/inbox).

You may create a forwarding file (“.forward” in your home directory). A simple forwarding file consists of a single line, which may contain:

• Your own address (e.g., simply gsm10); this instructs the mailer to ensure it creates a copy of each mail message in your .mail file, wherever else it may send the mail.
• An alternative address (e.g., gsm10@hermes.cam.ac.uk, or murchison578@hotmail.com), for convenience while you’re away from the lab.

  Warning: When you first arrive, it is possible that a .forward file will have been created for you, redirecting your mail to the contact address that was entered in the database for you. This may be a usable long-term address, but it is more likely to need replacing.

• A vacation message instruction (e.g., v-gsm10); see vacation processing.

In fact the .forward file may contain a comma-separated list of these items, so

gsm10,v-gsm10,murchison578@hotmail.com

(on a single line) would save the mail, alert correspondents to Murchison’s absence, and make a convenient copy of the mail in a Hotmail mailbox.

Caution: your ~/.forward file must not be writeable by anyone else. The mail system will reject it if it has any writeable bit other than owner. The command

chmod go-w ~/.forward

will ensure it’s in the right state.

Outgoing mail

Computers located within and managed by the Computer Laboratory can send outgoing email via SMTP to mail-serv.cl.cam.ac.uk port 25 (no SSL/TLS encryption and no authentication is required). Note that this will not work from home or from mobile devices (without a VPN connection). Using this departmental mail server has several advantages over using the Computing Service equivalents (smtp.hermes.cam.ac.uk, ppsw.cam.ac.uk):

• It accepts local addresses without an @ sign (e.g., sys-admin, gsm10, Giles.Murchison).
• The validity of local addresses can be verified instantly by the mail client when sending a message.

Mozilla Thunderbird: install the add-on Allow Local Addresses if you want to be able to enter local destination addresses without an @ sign in them.

Processing mail and dealing with spam

The Lab mail system will obey a program you write for it in your ~/.forward file. Many people choose to do pretty complicated things with their mail, but almost everyone wants to check for spam and dispose of it. For guidelines on how to get these things going, see the page on mail processing, which also contains pointers to further information.

Forwarding your mail after you leave the department

When you leave the department, you have the option that your Lab email will be forwarded (unless yours is a “stub address” — see above).

Plainly, we can not set up forwarding, even for appropriate account types, unless we have a usable email address for you. Typically, people will use their .forward file to set up forwarding, at the time they leave, but you may request an alternative address, by email to postmaster@cl.cam.ac.uk.

Note that forwarding to your ‘@cam’ address will typically not work; that address is deleted, by the Computing Service, shortly after you leave. If you were forwarding to your ‘@cam’ address, and then forwarding from there, copy the ultimate destination into your lab .forward file before you leave.

Note:

• Email forwarding will be cancelled if the forward gives us trouble (e.g., through bounces).
• Currently, we do not apply a spam filter to forwarded mail, but we reserve the right to do so (and to drop mail that is flagged as spam in the Computing Service Spamassassin classification).

Aliases and mailing lists

Are discussed in a page of their own.

Problem resolution

If you’ve exhausted the help you might find from your colleagues, you can mail postmaster for assistance.

If you need some non-standard mail support (for example, you want a different mail reader installed on your system), mail your request to sys-admin (the general systems administrator mailing address).