What you’re asking for is very easy with this plugin: http://premium.wpmudev.org/project/domain-mapping/ It does cross-domain cookie syncing with all of your sites on one Multisite installation.
I’ve used this a couple times and it works dandy.
Related Posts:
- Different Domains in Multisite Setup
- Infamous admin login redirect
- Some Subdomains on a Multisite Install Not Found
- How to use WordPress Multisite With Different Domain Names?
- Is there a is_user_logged_in() for multisite?
- Multisite Domain Mapping with SSL
- How to set up wordpress domain mapping on MAMP Pro
- How to use alias domain for multisite installation?
- WordPress Multisite with multiple domains using Nginx
- Unable to login to new custom domain on multisite?
- share login/logout sessions across two installs?
- sunrise.php for multi-network install of domain mapping plugin
- Is it still only possible to do multisite domain mapping with a plugin in WordPress 4.1?
- How to manage multiple domain with different languages on each domain with single wordpress installation?
- “Preview Changes” button doesn’t show changes for previously published posts/pages
- How to add new sites and map a custom domain in WordPress Multisite?
- WordPress multisite with different domain
- Trying to migrate a WordPress Multisite with Domain Mapping
- Multiple blogs, different domain names, one install to rule them all
- WordPress Multisite Login Access
- How do I use different domain for subdomains in WP Multisite?
- subdomain mulitsite on localhost in a subfolder
- WordPress Network for regional company websites
- How to do Domain Mapping to Subdirectories?
- Possible to create a multisite network where the main site is non-WP?
- Multiple domains with different child themes on one installation?
- ‘Remote Login’ with MultiSite Domain Mapping still forcing users to login to all blogs individually?
- How to stay logged in on a multisite with different domains?
- WordPress multisite with multiple parent domains
- WP 4.4 – domain mapping for sites within a multisite network?
- WP MU – Accessing ‘Domain-Mapped’ WP-Admin with a subdomain
- Fresh Multisite Install – Can’t Log In
- Create rewriterules for different domains in htaccess file with WP multisite
- Auto Redirect after login
- Multisite domain naming
- WordPress MultiSite login to the respective site
- WordPress MU Domain Mapping Just Redirects to Main Site
- WordPress Multisite with Addon Domains (not parked domain) [closed]
- Good way to block users within a multisite setup without deleting them?
- Mapping domains to WordPress network installed on subdomain
- WordPress 4.5+ Multisite Domain Mapping
- Link structure, WordPress IIS
- Multisite – Parent site with Polylang with different domains for each language [closed]
- WordPress Multisite + Erros with URLS and ADMIN
- How can you override the is_multisite check in wp-login.php for individual login/registration?
- Login problems on multisite installation with different domains
- Is this a job for WP MultiSite with domain mapping plugin?
- MU/Subdomains + Domain Mapping + SSL?
- network site domain mapping still applied after being removed
- How to set up wordpress domain mapping on MAMP Pro
- Domain Mapping for WordPress MU and https redirection – How to?
- Multisite domain mapping breaks CSS
- WordPress MU subdomain vhost
- Domain mapping with Multisite links are wrong
- Multisite Login problem
- How to Deny Access to No Referrer Requests on Multiste with Mapped domains
- Install multisite wordpress on a subdomain and map to top level domains
- Multisite – One Site with multiple URLs
- Sub-sub folders of WordPress Multisite subdirectory
- Https and Http Login Issue on WordPress Multisite
- WordPress Multisite with subdomains on different domains
- WordPress multisite with domains and subdomains
- Domain Mapping subsites of an Add-on Mulsite Domain
- Multisite infinite redirect loop
- Forward and mask a WordPress website
- Folder structure when using multiple domains with WordPress
- wordpress multisite domain mapping redirects to original subdomain
- Is there something I need to know in order to use WordPress on foreign (Swedish) TLDs?
- WordPress Multisite and how to apply sef urls only to specific sites
- multisite installed on subdomain now want another subsite on subdirectory
- Migrating from domain mapping plugin to native domain mapping
- Moving from a non WordPress site to a WordPress Site – Login between both sites
- How to map domains to specific pages in WordPress and display them in the address bar?
- Add file at the root of mapped domain in multisite
- WordPress Multisite with Wildcard Certificates not mapping correctly
- Login issues on WordPress Multisite and domain mapping
- SSL for Mapped Domains with WordPress Multisite on AWS
- Multisite htaccess with domain rewrites
- WordPress Multi site Map Domains
- WordPress Multisite: Login to all subsites at once
- new WPMS site not working / Q setting up new site/subdomain
- Optimal setup for Multi Domain WordPress with Woocommerce
- User not staying logged into one of sub sites in multisite after SSL
- WordPress automatic Login on other page?
- how to make a cronjob run, when user needs to be logged in
- WordPress Multisite with cPanel Addon Domains and SSL
- How to implement this subdirectory mapping in multisite?
- Why does this multisite redirection loop vanish when I add “www.”?
- MU domain mapping without using a plugin
- How to configure WordPress for multiple blogs without using multisite?
- Subdirectory and domain multisite installation
- Multisite: Redirect Subsite Administrator to Subsite Home Page, Bypassing Dashboard
- Admin user getting redirected to /wp-admin/user
- WordPress Domain Mapping shows new domain in place but takes me to the sub domain
- MU Domain mapping
- Common login for websites belonging in different networks
- Are there any hosting companies that are already setup and configured for TLD domain mapping?
- WordPress Multisite restict user access
- Map WP Multisite blog.example.com to anotherdomain.com/blog?
- Have two domains point to the same content on a wordpress multisite