I'll try to keep this as brief as possible.
I have two SBS 2008 servers. One of the servers acts as my email server along with various other "serving" applications like CompanyWeb, etc. I do not run my own web server. As an example, from the outside world we access our email by typing https://portal.OURDOMAIN.com.
We recently switched from AT&T to Comcast "Business Class" with 5 static IPs. We received a gateway from Comcast but nothing else. As far as I'm aware, the email hasn't been working since the transition (this is what others tell me), however, I was able to send a test email last night from a GMail account that I received just fine (it was somewhat delayed). Indeed, a coworker was apparently able to send me 3 emails last night around 7pm. Now, however, it's not working, even through Outlook in the office.
Now, whenever we try to access the "portal" from the outside world we get a 404 error that seems to be generated by our server. When we try to access it from inside the network, something strange happens. It goes to the HTTP page for the gateway and says that the certificate is invalid:
Certificate Errors when Attempting to Connect to portal.png 53.07KB 3 downloads
Even when I tried forwarding a bunch of ports to the server it doesn't seem to work:
Gateway port forwarding.png 29.46KB 3 downloads
When I try to access the portal from the server that it's supposed to be running from I get this:
Server Error in Application 'SBS WEB APPLICATIONS' (sanitized).jpg 140.37KB 3 downloads
Also, right after switching to Comcast we installed a new wireless router (an R6300) due to the gateway not having wireless routing capabilities. It's connected to the main switch. Actually, I made up a quick diagram of our network last night if it helps. It's a work in progress so if some things seem strange that's because we're still moving things around and running cables:
Network Diagram 1.0 (redacted).png 114.44KB 3 downloads
Also, the gateway and router have been been set up with the following settings (this is exactly how we have it set up with the only difference being that we have a Netgear router):
I could sit here and type a few more pages on the subject but I simply don't have time. I think it would be faster for me to present this basic info about the problem and then if someone thinks they might have a solution I can give more info as needed. Thanks in advance for your help.
*By the way, we are a small company (less than 10 employees) and don't have an on-staff IT guy. We basically just have two computer savvy guys running the whole thing. It's worked out fine so far. We always somehow manage to keep the thing up and running.