In the IDXpress > General Settings, there is a section to set a custom mobile domain:
Mobile Settings
To set up a custom mobile domain you must configure your DNS to point a domain, or subdomain, at app.dsmobileidx.com. Then enter the custom domain's full url here. Example: http://mobile.myrealestatesite.com
My DNS zone editor is expecting an IP address, not a url (like app.dsmobileidx.com), so I'm not sure what I should be changing the A-record for mobile to be.
Please advise. (hopefully I'm posting in the right place, a bit of a crossover between the products here)