I'm so exciting, because I'm working in a project with Cisco Meraki., but unfortunely I'm facing problems in the firsts steps. Maybe you could help me.
I enable splash page with AD authentication, our network is running with a IPFire proxy, the main problem is, when the user connect to Wireless Network, the splash screen is only displayed if I disable the Browser proxy server, and after the authentication is necessary to enable the proxy again to use the internet. I tried different ways and addresses to exclude the Splash Page from the proxy, but nothing is working.
That is not going to work with a proxy server configured.
Is this for internal "corporate" access, or for guest access?
If for internal usage for AD joined devices you should consider using WPA2-Enterprise mode instead. However you do need to deploy Microsoft NPS to be a RADIUS server and ideally a Microsoft CA server, so it is quite a bit of work.
You could also consider using Systems Manager, which allows you to automatically deploy certificates onto Windows machines and mobiles and then use cloud based Meraki Authentication.
The problem with a proxy @Adam is that it causes all the web browsing requests to be sent to a specific server, so the MR (or MX) never gets to see the request. And to trigger the splash page the user could be visiting any page on the Internet, so it is not possible to whitelist either.