Virtual Hosting at UVa
This document explains the concepts behind 'virtual hosting' and the
policies governing this system's use at the University of Virginia.
Information concerning configuring web server software is not
included. Please consult the documentation for your software.
Table of Contents
What is a 'virtual host'?
Virtual hosting is a way of letting one machine serve more than one
web site. Machines can get assigned aliases on the DNS (Domain Name
Service) level. DNS refers to a hierarchical series of databases that
allow machines to find each other on the Internet. For more
information about DNS, visit:
http://www.itc.Virginia.EDU/itcweb/networks/dns/host.html
For example, the machine minerva.acc.Virginia.EDU has the
aliases of www.Virginia.EDU and faculty.Virginia.EDU.
Although all these names refer to the same physical machine, the web
server software can be setup to serve out a different set of web pages
for each of these aliases. This way, going to www.Virginia.EDU
will display one set of web pages, but going to
faculty.Virginia.EDU will display another.
Setting up a virtual host is a multi-step process. First, the
University hostmaster (or an outside agency, if you have contracted
out this work) must assign your machine a DNS alias. After this
DNS alias becomes active, the system administrator of the host
machine must configure the web server to properly redirect users
to the desired site on the machine.
Because of the complexity behind the establishment of virtual hosts,
ITC strongly recommends that departments or organizations consider
other options to the creation of sites. These other options will not
require as much configuration on as many systems as virtual hosting
requires. Please look at the Alternatives to
Virtual Hosting section of this document before requesting the
creation of a virtual host.
Alternatives to Virtual Hosting
faculty.Virginia.EDU
Faculty working on a research project have the option of applying for a
site on the faculty.Virginia.EDU website. This option is the
most greatly preferred option because it can make a site URL unique
while requiring little reconfiguration by system administrators. A
detailed discussion of this site, as well as an application form, is
available at:
http://www.itc.Virginia.EDU/itcweb/networks/web/faculty.html
Top Level Links
On most web servers, the system administrator can place a top level link
on the system to redirect users to another directory on that machine.
These URLs take the form of:
http://machine-name.sub-domain.Virginia.EDU/linkname
where linkname is a mnemonic name for your site. For example,
the University's Registrar Office's site is:
http://www.Virginia.EDU/registrar
This setup requires little or no web server re-configuration and no DNS
changes. Administrative departments with homepages on the University
web server (www.Virginia.EDU) should contact the University
webmaster by writing to webmaster@Virginia.EDU to get a link
established a site. Other departments or other people should contact
their system's administrator.
Outside ISPs
Should ITC reject your request to host a non-Virginia.EDU website, or
should you want a virtual host for a private homepage, you have the
option of contracting with an outside ISP (Internet Service Provider)
to provide this service. Cornerstone
Networks is one area provider that handles this service. Other
such ISPs exist on the web. You can use a search engine such as Yahoo.com to locate one that can suit your
needs.
Guidelines for virtual hosting DNS
assignments
DNS guidelines
Because of the limited number of IP addresses available to the
University, ITC will assign, with few exceptions, only one IP address
to each machine on the University network. In the past, setting up
virtual hosting on a web server meant that your system needed one IP
address per virtual host. Now, most web servers can use DNS aliases to
distinguish between the sites on a machine. ITC can create DNS aliases
within the existing sub-domains (for example, itc.Virginia.EDU)
provided that the system administrator of that machine is willing to
configure that machine to handle this virtual host. Check with your
web system's administrator before requesting the creation of a DNS
name.
Outside of creating names in existing department sub-domains are the
options to create new sub-domains and the option to create a name in
the top of the Virginia.EDU hierarchy. Creating a name such as
www.foo.Virginia.EDU, for example, requires that the sub-domain
foo.Virginia.EDU exist in DNS. On the other hand, creating a
name such as baz.Virginia.EDU where there is no departmental or
organizational sub-domain is a top-level DNS alias. Please note that
any name requested that is too generic as to allow confusion or
conflict between organizations or departments will be rejected. In
addition, ITC will reject any name that could misrepresent the
University or any of its departments and organizations.
ITC will only consider the creation of new sub-domain if one of the
following criteria are met:
- The requested name is that of a department or the recognized
abbreviation for a department.
- The requested name is that of a multi-department project or
organization. The name for DNS must not conflict with other project or
organization names.
The creation of top-level Virginia.EDU aliases should meet all
the following criteria:
- The name chosen for this alias clearly identifies the service, the
project, or the organization. If using a service name, this service
must be unique to the organization requesting the creation of the
alias.
- If the name requested is for a research project, then this project
should span multiple departments or multiple organizations.
Aliases for research projects confined to a single department should exist
within that department's sub-domain, if one exists.
- A need exists where tying a DNS alias to an existing department's
sub-domain will affect the project's success.
Information for obtaining these DNS changes are listed in the procedures section of this document.
Names used in DNS should not misrepresent the University or any of its
departments. ITC handles all requests on a 'first-come-first-served'
basis. ITC also reserves the right to charge for the creation of new
DNS aliases and/or sub-domains.
General Guidelines
The purpose of these sites must conform with the University
academic and/or administrative goals. Requests for virtual hosting for
personal homepages will be rejected. University policy prohibits the
use of University equipment or other computing resources for commercial
ventures.
For more information on the University's policy on the use of its
computing resources, please look at:
http://www.itc.Virginia.EDU/department/policies/pcr.html
ITC reserves the right to charge for this service.
Procedures for Obtaining DNS Aliases
Aliases with an Existing Sub-Domain
ITC can create DNS aliases in a department's sub-domain for machines
not maintained by ITC. To request a DNS alias in an existing sub-domain,
submit the request form at:
http://www.itc.Virginia.EDU/itcweb/networks/dns
Aliases in the Top-Level Virginia.EDU Domain
ITC will grant a top-level Virginia.EDU alias for services that are not
likely to duplicated elsewhere in the University and for services that
serve the entire University community. For example,
www.Virginia.EDU is a top level alias that serves the
University's main departmental webpages. Faculty or departments
working on a sponsored research project can also apply for a top-level
alias, provided that it conforms to the guidelines listed in the section above. To
request this service, write to hostmaster@Virginia.EDU
summarizing the purpose of this site, the alias that you want, and the
machine to which the new alias should point.
Aliases in a New Sub-Domain
ITC will normally not create a new sub-domain for departments,
especially not for the purpose of virtual hosting. If, however,
your department does not have an existing domain, or if you are
working on a sponsored research project, please write to
hostmaster@Virginia.EDU explaining your DNS needs and why
you need a separate sub-domain.
Virtual hosting of non-Virginia.EDU addresses
The University does host some outside domains (non-Virginia.EDU names)
for some departments. These domains must be closely related to the
academic and/or administrative goals of the University. Folks that
want ITC to host these names should submit a request to
hostmaster@Virginia.EDU detailing the nature of this site as
well as the need for the non-Virginia.EDU name. One or more of the
following criteria must be met for these requests:
- The requesting organization is a consortium of many departments
from multiple universities and the University is hosting the site.
- The organization is conducting a project where having a
Virginia.EDU name would adversely affect the project's results.
If approved, ITC will register your domain name for you through one of
the accredited Internet Registrar services. ITC will levy a small
charge for this service to recoup the fees involved for registering
Internet domain names. Requesting a domain within the existing
Virginia.EDU hierarchy, however, does not carry a charge.
Getting help
Questions about virtual hosting policies should go to the University
hostmaster (hostmaster@Virginia.EDU). Other web related
questions and inquires should go to web-consult@Virginia.EDU.