Nginx config, how can I redirect primary multisite domain, but not its sub-folders, nor other domains?

Question

Environment

This environment is Nginx with Wordpress Multisite installed.

Question

I need to redirect the primary multisite domain (e.g. domain.com, www.domain.com) to another domain (e.g. domain-new.com, www.domain-new.com). But I don't want sub-folders to redirect. For example, the /wp-admin/ folders needs to NOT redirect, otherwise I'll be unable to administer the multisite network.

Obviously, I don't want any other domains to redirect. Just the one stated above.

I found instructions on how to do this in Apache, but I haven't been able to figure it out in Nginx.

What I came up with so far

I came across the following:

server {
  listen 80;
  server_name domain.com www.domain.com;
  rewrite ^ $scheme://www.domain-new.com$request_uri permanent;

But this will also redirect sub-folders of domain.com. I was to sure how to make it exclude wp-admin folder from the redirection.

I also came across this option:

location = / {
rewrite ^ http://domain-new.com/$uri permanent;    
}

But I couldn't find anything on whether the location command can include a domain, and if it can, how to ensure a specific sub-folder (wp-admin) is not included in the redirect?

Answer 1

If your nginx server block is handling multiple domains, the simplest solution would be to test the $host parameter within an if block. Also, change the rewrite statement so that it only matches a single URI.

For example:

if ($host = domain.com) {
    rewrite ^/$ https://new-domain.com permanent;
}

This is placed near the top of the existing server block.