Iis – How to set up second IIS website with different domain name on a single server

You can't do it from the UI, you have to do it from the command line. Here's a nice walk through of the process:

http://www.sslshopper.com/article-ssl-host-headers-in-iis-7.html

1. For email, I don't think you can do this with DNS. The only time DNS is involved with mail is for determining which server to send mail to for the requested domain. So whilst you can have the MX records for both domain1.com and domain1.net pointing to mail.domain1.com, say, you will need to configure that server to accept mail for both domains, and route it to the correct mailbox as appropriate. Exchange will do all of the above out of the box.

For web requests, (and this answers #3 too), it depends on whether you care about the host name that ends up in the address bar of the browser. If you don't then you could just CNAME www.domain1.com to www.domain1.net, and as long as you have both hostnames as vaild host headers for the site in IIS/Apache, the page will load and all will work. I wouldn't recommend this however as all it takes is one absolute href and the user is bounced to the other domain, not to mention issues with SSL and wider business branding problems, SEO, the list goes on.

To do that properly, use a redirect rule and bounce all traffic to one domain.

2. IIS redirect is the neatest way, keeps everything consistent. You could just add A records for both in DNS and add both as accepted host headers for the site in IIS though. Up to you.

3. As 1. but bear in mind that if you want to use SSL you will need a dedicated server IP for each site, so it might be simpler to redirect everything to one place and then secure that.

HTH