ucam.org domain names
A centrally-maintained list of Cambridge student-run machine names and
their full canonical DNS names is kept, so that users wishing to refer
to any such machine from a system which mentions ucam.org in
its DNS search path need to type only the bare hostname.
Some misguided people will only issue hostnames to students which are
generated in some poor way (for example, by requiring that the user's
machine's hostname be their username). Such machines can have a more
sensible names in ucam.org.
Administrators of services on student-run systems can use and publish
service names for them, so that the service can be moved to different
systems transparently when required.
Finally, to provide a mail domain and www site that can be used for
miscellaneous Cambridge activity associated with ucam.chat and the
The ucam.org DNS zone contains, largely, CNAME (ie, alias) entries for
the student-run systems. In most cases these are a simple alias which
maps, for example, exemplar.ucam.org to
Allocation and Change Request Procedure
Requests for allocation of names, changes, fault reports, etc, should
be sent by email to
For a simple alias, please state:
- the name you want in ucam.org (see below);
- the machine name (not IP address) that it should refer to;
- the name and email address of the machine's administrator, if
that's not you.
Prospective domain owners should read
(RFC1178), `Choosing a name for your computer'. Names should be
neither too short nor too long. We will not usually issue names that
are simply the name of the domain owner, and you are strongly advised
not to use your CRSID (ie, CS-issued userid). We'll avoid issuing
names that clash with well-known CS and Departmental systems.
Names in ucam.org will usually be handed out first come first served
to members and staff of Cambridge University and the Colleges. They
will persist while they are still being used, unless the owner
requests that they be removed. If a name falls into disuse it may be
Societies will not usually be allocated society-name.ucam.org;
instead, societies will be allocated abbrev.soc.ucam.org. We're
aware that there is a lot of collision in society acroynms; they are
on a first come first served basis, but it would be nice if people
could try to pick likely-to-be-unique abbreviations rather than
We'll usually accede to requests for aliases for systems in cam.ac.uk
made by other than the system's owner, but the owner will be informed
and we'll remove the alias if they object (or change it if they prefer
a different name).
`Meaningful' names such as (for example) people.ucam.org and
pubs.ucam.org are allocated on a different basis: they are
allocated for the particular purposes that you agree with us in our
In the unlikely event of some kind of dispute between competing
claimants we'll have to make a decision as to who or what is the best
group or way to provide the service, so we reserve the right to revoke
the allocation of such a meaningful domain name and to allocate
subdomains to different people or some such (though we hope never to
have to exercise it).
If the activities you'll use the name for are related to the meaning
of the name itself then you should let us know, either when you
request the name or when you propose to change the use in this way.
CRSID's (Computing Service usernames) and `namespace' uses
We will not allocate a domain of the form crsid.ucam.org to
anyone but the owner of the CRSID. You may therefore use your CRSID
to generate a personal unique domain name and use it whereever
appropriate (eg, Java class names), without consulting us.
We recommend that you do not name your computer(s) after your CRSID.
It is a bad idea to give a computer your own name in this way, for a
number of reasons. See the advice in FYI5, aka RFC1178, `Choosing a Name for Your
You may find it useful to inform us of your use of the CRSID. This
will help avoid us accidentally allocating your name to someone else
(eg, because we didn't realise that they weren't you), and can also
help avoid problems in the rare cases where the Computing Service
reissue a CRSID to someone else.
Relationship with the University Computing Service
CS Conditions of issue
of IP addresses (10th February 1999)
You should not cause address(es) or name(s) to be registered in
any other part of the DNS without previously consulting the
Computing Service as such aliases can give a misleading impression
about the proper use of the CUDN, JANET and other networks, and
can cause confusion leading to the waste of network staff time.
According to a mail to Ian Jackson from Tony Stoneley in January 1998,
As far as I'm concerned, the consultation referred to therein has
happened in respect of ucam.org with its current style and purpose.
Note that publishing a name in ucam.org for a service rather than a
name in cam.ac.uk doesn't obviate the need for you to comply with the
JANET, CUDN and College AUPs.
More complex activities and requirements
Web site aliases
It is of course perfectly fine to use a name allocated to you in
ucam.org for a website. You will have to find a system to do the
actual hosting; have their administrator contact firstname.lastname@example.org,
CC you, with the ucam.org allocation request.
If you have been allocated (or are requesting) a domain in ucam.org,
exemplar.ucam.org for example, and need a service alias,
www.exemplar.ucam.org for example, just ask.
(A service name is a name that refers to a service rather than to a
particular host. Service names are a good idea because they make it
much easier to move a service without publishing a new name for it.)
Departure of a ucam.org host from the CUDN
When a host named in a ucam.org alias leaves the Cambridge network its
name and address will be deallocated from Cambridge's namespace. When
we notice that this has happened we will usually delete the relevant
alias, and free up the name in ucam.org for reallocation. If
continuity of service is desired then you need to let us know what the
new hostnames are so that we can change the aliases.
If the new systems are not in the CUDN then this is fine. However:
Normal consumer-level ISP service cannot usually be made to handle
providing service under a ucam.org alias. For example, if we were to
make www.exemplar.ucam.org an alias for
www.exemplar.demon.co.uk then it wouldn't work properly,
because Demon's webservers would not know which pages to deliver for
www.exemplar.ucam.org when they received the requests.
Similar considerations apply for mail and most other internet
If you wish continuity of www service, or other services, then you
need to get someone to actually host those services. This could be a
competent person with a permanently network-connected system who is
willing to do you this favour, or a commercial ISP that you've paid
the relevant (usually much higher) amount of money. In either case
the hosting systems' relevant technical people should contact
email@example.com so that the details can be sorted out -
either addition of the appropriate DNS RRs to the ucam.org zone, or
delegation (but see below).
We will usually be willing to delegate a subdomain of ucam.org, if you
can find somewhere to run the primary nameserver and someone competent
to edit the zone file.
- You must comply with all the CS's requirements if you are going to
be using their network. For example, if you wish to run the primary
nameserver in the CUDN, or do other things that the CS might object
to, you should talk to the CS first.
- For technical reasons, if the domain you wish to be delegated is
directly under ucam.org (eg, exemplar.ucam.org instead of
experiment.exemplar.ucam.org) then there should be at least
three nameservers, one of which is on the CUDN, and all of the
nameservers should be reliable. We can arrange for a secondary -
contact us for details.
- You must allow outbound zone transfers to all comers.
- You must have at least two nameservers. Three is usually better;
we can provide a tertiary server.
- Granting a domain, or delegating a subzone, in ucam.org does not
imply that the ucam.org administrators will be willing to host mail
relays, virtual web servers and the like, on their systems. If you
want these facilities you will have to obtain them separately.
For a number of technical and political reasons it is hard to make the
aliases in ucam.org be mail domains. If you think you know of a way
to do this, please consider the following points:
- The system named in the MX records would have to be willing to
handle all the mail for the relevant domains. (The ucam.org
administrators are personally in general not willing to do this.)
- An MX record and a CNAME record cannot coexist at the same place
in the DNS. That is, a name cannot be both a mail domain and an alias
to something that isn't a mail domain.
- At the very least politeness would require us to consult the CS.
Things need to be arranged so that the CS aren't exposed to internal
details of the arrangements, even when the inevitable problems occur.
- What about enormous mail queues during the holidays ?
- Many of the most obvious solutions in fact involve nontrivial
research, programming and/or administration.
- Email addresses in ucam.org would be even more ephemeral than
students' CS-issued addresses. Ephemeral email addresses are often a
- Someone competent would have to be willing and available to chase
up the inevitable incompetents when their mail systems go wrong.
Ian Jackson as
ucam.org main page
Campaign for a non-browser-specific WWW