I have setup a new Exchange 2010 server and I am migrating from Exchange 2003. I have an internal domain name of 123.org and an external domain name of abc.org. I have created a certificate request and was attmpting to purchase the cert from Digicert. The rep at Digicert told me that I could not buy the SSL cert because my internal domain name of 123.org is a registered external domain name of another comapny. My problem is that I am not sure how to remedy this problem. The rep I was speaking with got in touch with his Exchange cert expert and they directed me to this article http://support.microsoft.com/kb/940726 and told me to change the internal settings to use the domain name of our external domain name which is abc.org. Will this work to fix my problem? And will this cause any problems on the internal domain name? Lastly, would it be best to purchase a wildcard certificate or a SAN certificate. It seems like it would be simpler to manage it it was a wildcard cert. Once the migration is complete I will only have one outward facing Exchange server, so hopefully there would be no security problems with using the wildcard cert. Thanks, Doug

To add to Adam. Or you register the domain name you use internally so no one else can get it, but you don't have to publish it on the Internet. What I am getting a feel for here is that you have not planned out all the aspects of your Exchange 2010 design. This should be done prior to submitting certificate requests. Make sure you understand the CAS namespaces that you are using and map them out, e.g. http://technet.microsoft.com/en-us/library/dd351198.aspx If you have split brain DNS, then you can do what Adam suggests and use the same names internally and externally. You will need to configure ALL URLs and not just AutoD. Again this goes back to namespace design which is 90% of CAS work, the remaining is 5% implementation and 5% test. Numbers can be changed, but you get the idea :) Remember to consider activesync, Outlook Anywhere, Autodiscover, EWS, OAB, ECP......... Cheers, Rhoderick

Hello, Share with you a nice article: More on Exchange 2007 and certificates - with real world scenario http://blogs.technet.com/b/exchange/archive/2007/07/02/3403301.aspx Thanks, Simon

Hey guys, Sorry for the late reply on this, but I have been out of town for a few days. Thanks for the great replies. It looks like I will go with what Adam states. He hit it right on the nose about the internal domain name matching another companies internet domain name. Because we do not own that domain name Digicert would not issue us the cert. Had I known back in 2004 that MS would someday make a new Exchange server that would require using an SSL cert for both internal and external security, I probably would have named the internal domain name .local or .internal or something like that. With that said, it looks simple enough to change the CAS names for internal resolution. As long as no one gets the certificate error then it's all good. I will probably be installing the cert byt the end of this week. I will post my results and more thanks here when I get it to work. Thanks again, Doug

Well, I finally got the server going on Saturday morning and after changing all the internal names to abc.org domain name everything worked just fine all weekend. So, thanks for the input here. Now I seem to have another problem that just popped up today. The problem is that when I create a new outlook profile on a workstation it tries to connect to mail.abc and not to mail.abc.org. So now I get a certificate error mismatch with the certificate name. for some reason my DNS server was resolving mail.abc to some ip address on the internet. I have no idea why this is happening, but I came up with a cheap and easy fix. The fix was to create a new zone called mail.abc. In that zone I created a blank A record with the ip address of my Exchange 2010 server's internal ip address. It seemed to do the trick for now, but I would like to know why this happened in the first place. Any help would be greatly appreciated. Doug BTW, the certificate that it was seeing was a cert registered to Open DNS. We use Open DNS as our external DNS servers.