Internet access to Wildfire

I have a few remote users who access their email via Outlook Web interface. This voids me having to give them VPN access. I would like to explore the options of allowing them to access the Wildfire server via the internet. I currently use LDAP and obviously only allow secure connections to the server. Can I just simply open up port 5223 to the Wildfire server? Will this allow them to authenticate and access the Wildfire server?

Please look for the answer in the other (duplicate) post: