Connection dropped by remote host error when a telnet is done to SBS/Exchange

OK so this past week we started working with a new client that had received a nice new Dell with SBS installed. The original tech (ok he was more of a business consultant turned tech) did a nice job of trying to getting everything running but it wasn't quite there.

After getting a new DSL provider (they were on cable) (oh yeah it's Lightning Bolt DSL, highly recommended. Static IP for a real decent price. www.lbdsl.com) and setting up all the proper information and making sure we got a good connection we started to reconfigure the network.

We went back and did all of the standard settings and reset up IP configurations to what we use as standard. 192.168.1.x on the outside subnet and 192.168.16.x on the internal subnet. This of course meant we needed to reconfigure the NIC settings for new IP ranges, new DHCP, and then rerun the Internet connection wizard.

Everything looked great. We could send email but alas now there was a problem. When trying to telnet our Exchange Server on port 25 we were getting the error message, Connection dropped by remote host. What the ? We had reconfigured everything properly and rechecked the IP's.

Well I started to look over the Exchange settings and here's what you will need to change, especially if you change the address of the server:
1. Go to Server Management
2. Go to Advanced Management
3. Go down to your First Information Store or Exchange management
4. Expand selections and go to Servers. Expand your server name.
5. Go to protocols, SMTP and click on the properties of the SMTP virtual server.
6. Make sure that in the General tab your IP address isn't your old IP address. In a normal SBS setup it will be (All Unassigned). However with these changes it's good to change it to the external NIC IP address. In our case it was 192.168.1.x.

Restart the SMTP service just to be safe and there you go. Now when you telnet domainname.com 25 you'll get the SMTP service.