Hi Carl1959,

>do I need to join this server to the domain?

WSUS server is not domain based, so there's no requirement that we must join the WSUS server to the domain. You can join to the domain, not join is OK too.

>If the latter, where's the procedure for making it a member server please?

If you want to make a server to be domain member, you can configure here:

Detail information about deploy WSUS 2008R2:

https://technet.microsoft.com/en-us/library/dd939822(v=ws.10).aspx

Best Regards,

Anne

https://social.technet.microsoft.com/Forums/windows/en-US/15c28bc8-e28e-4b67-913e-d27597fdb435/do-i-have-to-join-wsus-server-to-domain?forum=winserverwsus