What would happen if I give a DC or a machine joined to a DC a static IP? Bad practise?

Active Directory is very tightly coupled to DNS. DNS relates the IP to a hostname.

If the IP is always changing on a machine, by way of a dynamic IP, would this make it a very bad idea to join a machine to a domain?

A DC is also recommended to have a static IP. Is this for similar reasons (ie it would be hard to resolve the IP to hostname if the IP is always changing).

For example, in the enterprise, for machines to be joined to the domain, we are always given a block of static IPs so I guess I must be on the right tracks?

Thanks

Solution 1:

You're right in saying that Active Directory is tightly coupled to DNS. However, if what I think you're asking is "are static IPs a bad idea?", then no, they're not. Quite the opposite.

It is a generally accepted practice to make all servers and printers in an organization have a static IP address and utilize DHCP for managing the rest of the network via scope.

You can use DHCP for keeping track of static (not manually assigned) IPs via reservations.

The way we do it in our network is we have a scope to accomodate all user PCs. There are some static IPs (in the scope) that we assign via reservation (for those machines that require a static IP). All other IPs fall outside of the scope area and are static (manually assigned) IPs for servers, routers, firewalls, printers, etc.

Solution 2:

A domain controller must have a static IP.

Client machines can have dynamic IPs because of dynamic DNS record updates. It is not a great idea to assign static IPs to clients, it is much much easier to let DHCP do that.