1. General Information
A proxy caching server is a system which sits between your web browser and the Internet. It acts as an intermediary (or "proxy") by fetching pages on your behalf, which it forwards to your browser. It also saves a copy of each document it retrieves to form a collection (or "cache"). The next time that a cached document is requested, the server returns it from the cache instead of going off to the internet.
The time that objects are retained in the cache varies according to load. However, once an object has been in the cache for three days the server regards it as "stale" and will go and check the originating server if it is requested. The cache uses information in the headers returned by a remote webserver to determine how long it can retain an object without revalidating it with the server: see this flowchart for more information. You can force the server to re-fetch content with the "Reload" or "Refresh" button on your browser (or possibly shift+reload/ctrl+refresh).
The "cacheability" of a given page may be checked using the very useful tool at http://www.ircache.net/cgi-bin/cacheability.py.
If your machine is not within the Oxford network, please do not attempt to use the OUCS proxy cache, as it will not work. Refer to your local IT support officer or your Internet Service Provider for information regarding proxies.
If your machine is within the Oxford network, please first check that a local configuration problem is not to blame, and if not, then contact us on firstname.lastname@example.org with details of the problem and we will attempt to resolve it as soon as possible.
There are several possible reasons for this, some of which are given in the error page returned. Essentially, it means that the proxying software is unable to process the request submitted. If you are unable to solve the problem, please contact us with as much detail as possible and we will look into the problem for you.
Such URLs are technically invalid (according to
However the caching software implements a workaround for such URLs:
whitespace characters are "escaped" through conversion of the ASCII
character code to hexadecimal. For
instance the invalid URL
may be called instead with
This conversion in itself may be considered a breach of standards, but does
at least permit such URLs to be accessed.