As part of a planed migration from a server-oriented infrastructure to a service-oriented infrastructure, we have recently made changes the way the caching proxy servers work. For most people, the effects of these changes will be transparent as they'll pick up the correct settings from the proxy autoconfiguration file at http://www.ru.ac.za/proxy.pac or via DNS if they're using wwwproxy.ru.ac.za/cache.ru.ac.za in a static configuration.
This message is informational and is aimed at users who have unusual configurations.
Each server running a caching proxy server now binds a separate IP address that is dedicated to serving cache traffic. These IP addresses MUST NOT be used for any other service -- they're exclusively for web traffic passing through the cache servers. Each IP address resolves to a name of the form *.cache.ru.ac.za (where the * is a letter such as a, b and f and refers to a specific instance). This address is used for both client traffic and outbound web connections, meaning that clients will no longer connect to the server's primary IP address. There are presently three cache servers in this scheme: a.cache.ru.ac.za, b.cache.ru.ac.za, and f.cache.ru.ac.za.
The use of cacheX.ru.ac.za (e.g. cache1.ru.ac.za) is now officially depricated. Anyone who has made use of the old numbered aliases should update their configurations to reflect the new naming system. For most people, this means that they should be refering to the proxy autoconfiguration file at http://www.ru.ac.za/proxy.pac or using wwwproxy.ru.ac.za in a static configuration. Those people whose unusual circumstances force them to use explict cache names should make use of the new lettered *.cache.ru.ac.za scheme for refering to the caches.
In order to give people a chance to update their configurations, the existing cacheX.ru.ac.za aliases have been updated to become CNAMEs to caches in the new *.cache.ru.ac.za naming scheme. Users should be aware, however, that the cacheX.ru.ac.za aliases will eventually be deleted.
In the same way, people who have elected to use IP addresses rather than DNS should note that the cache servers running on 146.231.128.1, 146.231.128.4, 146.231.128.32 and 146.231.128.96 (hippo, skink, squirrel and hipro respectively) will cease to function at some date in the future.