Redirect subdomain in Multisite installation?

Question

One of my clients has a Wordpress site that is a multisite installation. They are running a new campaign that I have set up as a page under the main site at example.com/summer/. However, they sent marketing materials to print that list the URL as summer.example.com. Is there any way to redirect that subdomain to the proper page without having to set up a whole new multisite?

I tried sending the A record of the subdomain to the IP address of the site. Then used .htaccess and added the following lines:

RewriteCond %{HTTP_HOST} ^summer\.example\.com
RewriteRule ^(.*)$ https://example.com/summer/$1 [R=301]

That redirects the subdomain to example.com/wp-signup.php?new=summer

Any ideas?

Update: I've added the wp-config definition of ('NOBLOGREDIRECT', '%siteurl%') which gets summer.example.com redirecting to example.com. This is not the fix I need, but just reporting back on potential fixes I'm seeing around.

Answer 1

RewriteRule ^(.*)$ https://example.com/summer/$1 [R=301]

You need to include the L flag on the RewriteRule directive, ie. [R=301,L] and ensure this rule is near the top of the .htaccess file, before the existing WordPress directives.

Without the L flag, processing continues and the request is further rewritten (by the WordPress front-controller) before the eventual (incorrect) redirect.