When someone browses to a URL, their browser extracts the hostname from the URL and uses the 'Domain Name System' (DNS) to locate the corresponding server. For this to work, the hostname or hostnames associated with each MWS Web Site need to be registered in the DNS.
Hostnames ending .cam.ac.uk
For most hostnames ending '.cam.ac.uk', this happens automatically when you associate the hostname with an MWS Web Site (see Routing requests to MWS Web Sites).
For most simple requests the managers responsible for the name you have chosen will be asked to approve your request and you can expect to hear the outcome within a few days, perhaps sooner. Changes to the DNS take time to become visible. Allow at least a couple of hours and possibly up to a day after a change is approved before expecting it to be visible from browsers.
If the hostname is already in use it may not be possible to set it up automatically and you will need to discuss your requirements with the relevant administrator (probably the IT staff of the associated department). For more technical details of this process see MWS DNS management.
For hostnames ending in something other than '.cam.ac.uk' you will need to manage the registration yourself, or get someone to do it for you. Your Domain Registrar will probably provide a control panel that lets you manage your hostnames along with instructions. If your domain is managed by the UIS Managed Zone Service then you can manage it at https://www.mzs.csx.cam.ac.uk/.
You can find the hostnames and IP addresses of your MWS server on the front page of the server's Control Panel, e.g.
Wherever possible set up your selected hostname as 'CNAME' (i.e. alias) for the underlying hostname of your MWS server, using your domain registrar's control panel. For example for names hosted by the Managed Zone Service:
or for a name hosted by a third-party Domain Registrar:
Because of DNS limitations you can't do this for some hostnames. Most often this affects hostnames that are the same as the name name suffix you bought, for example if you bought example.com and wanted the hostname example.com to behave the same way as www.example.com. For these you need to set up your selected hostname as the the IPv4 (and IPv6 if supported) addresses of your MWS server. You can find these addresses on the front page of the server's MWS Control Panel. On many registrar systems the symbol '@' is used to stand for the suffix itself, e.g.
'A' and 'AAAA' DNS entries are not supported by the Managed Zone Service.
Changes to the DNS take time to become visible. Allow at least a couple of hours and possibly up to a day after a change is approved or made before expecting it to be visible from browsers.