- Can you make a site collection available through the internet?
- Any good guides to getting them pointed externally?
- Is it possible to have a site collection that is available through different URLs internally & externally? (e.g.
1) Yes. This is possible. The scope of your requirements have not been defined, so if you require anonymous access, I have included links for how to do that. If not, ignore those links.
For Anonymous users : You need to first Enable Anonymous Access on the web application in Central Admin (Check out Authentication Providers). You will then need to make some content available to Anonymous users within the Site Collection. You will also need to sort out External DNS so traffic can be routed to your SharePoint server.
For regular users with logins : You need to sort out your External DNS to route traffic to your SharePoint server. Without knowing what DNS service you use, I cannot really give you a guide for this.
You will also need to make sure that there are no Firewalls restricting access on port 80 or 443 (depending on port being used).
2) Here are Anonymous Access guides :
https://www.youtube.com/watch?v=s9tigJk95fo (SharePoint 2013)
https://www.youtube.com/watch?v=iodlUnwlHUg (SharePoint 2010)
3) If you require multiple URLs to the same content You would need to configure Alternate Access Mappings in Central Admin, and also potentially set some Bindings in IIS if you require multiple ports for your web applications. You can have up to 5 different URLs that point to the same content.
If you require different authentication mechanisms for these different URLs, instead of just using Alternate Access Mappings, you may need to Extend the Web Application. This will allow you to serve the same content, but use a different URL and different Authentication mechanisms (like NTLM / Kerberos / ADFS / Forms based auth etc.)
https://www.youtube.com/watch?v=3s_uY983LXM (Volume is a bit quiet on this)
https://www.youtube.com/watch?v=WOE5WGAfF08 (extend Web Application)
Some good write ups on Host Name Site Collections :