Talisa @ Page Authority

Allowed Email Domains gives administrators a simple way to restrict WordPress user accounts to approved email domains.
The plugin is designed for sites where only users from specific organizations, companies, clients, or teams should be added as WordPress users.
Features include:
<ul>
<li>Admin-managed allowed domain list</li>
<li>Standard WordPress registration enforcement</li>
<li>REST API user creation/update enforcement</li>
<li>WooCommerce registration enforcement</li>
<li>Existing User Audit tools</li>
<li>Optional login enforcement</li>
<li>Per-user unauthorized account removal with content reassignment</li>
<li>Multisite-aware protections</li>
<li>Lightweight architecture with no custom database tables</li>
</ul>
<h3>Security Notes</h3>
The plugin includes:
<ul>
<li>Capability checks</li>
<li>Nonce verification (verified before any state-changing logic runs)</li>
<li>Sanitization and escaping</li>
<li>Live revalidation before destructive actions</li>
<li>Current-admin protection</li>
<li>Multisite Super Admin protection</li>
<li>Explicit content reassignment or delete confirmation before user removal</li>
</ul>
Recommended operational practices:
<ul>
<li>Review the Existing User Audit before enabling login blocking</li>
<li>Test custom registration and SSO flows before production rollout</li>
<li>Maintain regular database backups before deleting users</li>
<li>Restrict plugin management access to trusted administrators only</li>
</ul>
<h3>Uninstall</h3>
Deleting the plugin removes its current options:
<ul>
<li><code>pageauth_allowed_domains</code></li>
<li><code>pageauth_audit_log</code></li>
<li><code>pageauth_block_unauthorized_logins</code></li>
</ul>
It also cleans up internal flags, transients, user meta, and any leftover keys from prior plugin versions that used the <code>paad_</code> or <code>aed_</code> prefixes. On multisite, the matching network options are removed as well.

Page Authority – Allowed Domains

Restrict WordPress user accounts to administrator-approved email domains.

Steveorevo

Domain Theme allows you to specify more then one domain name with your WordPress installation and optionally associate a specific theme for each domain. This enables you to present your site under multiple domain names. (i.e. www.mypersonalblog.com and www.myprofessionalblog.com). A specific theme template can be assigned to a specific domain. For instance, you can use this plugin for a personal blog that has a casual theme under one domain and and present the same data under a corporate theme that omits select categories (i.e. family photos, etc.). You will need to modify your DNS settings to point your domain name(s) to the same server to make this happen.
Known Issues:
<ul>
<li>
Upgrade users from WordPress 2.6 to WordPress 2.6.1 who used version 1.2 may have incompatible domain data. Please delete and recreate your domain list.
</li>
<li>
All-In-One SEO users should delete their “Home title” setting otherwise it will overwrite the blog title settings in Domain Theme.
</li>
<li>
Please note that accessing wp-admin pages from any other domain name then your primary domain specified in ‘General Settings’ will cause the administration panel to report the ‘themed’ settings. Just remember to access your ‘General Settings’, ‘Presentation’, and ‘Domain Theme’ admin pages under your primary domain name if you want to make such changes.
</li>
<li>
Users before version 2.5 will have a minor UI issue on the Domain Theme control panel’s ‘delete all’ checkbox column. It will not check off all listed items.
</li>
<li>
The first item in the Domain Theme list cannot be deleted as it is the settings you have for your primary domain taken from the ‘General Settings’ and ‘Presentation-Theme’ page. Clicking it to edit will simply transfer you to the ‘General Settings’ page. This is on purpose.
</li>
<li>
Some users may have issues with their server variables SERVER_NAME versus HTTP_HOST. Simply uncomment the first line of code in the plugin if your additional domain names do not appear to work. See the comment on the first line of code.
</li>
</ul>

Domain Theme

Domain Theme allows you to specify more then one domain name with your WordPress installation and assign individual themes to each one.

Page Authority – Allowed Domains vs Domain Theme