Create A Network « WordPress Codex

Create A Network « WordPress Codex: "You only need wildcard DNS for on-demand domain-based sites, despite the advice that may be on the screen.

Once more: See Before You Create A Network.

Sub-domains — a domain-based network in which on-demand sites use subdomains
Sub-directories — a path-based network in which on-demand sites use paths
Network Details

There are filled in automatically, but you can make changes."

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