I also use different companies for registrant and hosting. For hosting I run a virtual server on Rackspace (formerly Slicehost). In most cases you want to do something like this. > > For testing stuff at home, you can always just edit /etc/hosts on your > testing box, as that will take precedence over external DNS records. > Nope. The /etc/hosts of the _client_ machine (the machine querying the IP to connect to the presumed mailserver) will need this modification. ONLY if you are testing from the box that runs the web/Horde server itself this will work. I am guessing this does not apply here; he probably wants his employees to test-use Horde from outside. In that case, the DNS record has to point to the IP where "home" is. This can be done. Make the webserver running at "home" have a virtual host that uses the hostname of your "presumed mailserver" of your domain. (This is easy to do.) Then, make the DNS record of your mailserver to point to your IP where "home" is. This can be an issue if you do not have a static IP there. Finally, you can point people to your presumed mailserver's _hostname_ and your box at home will respond as expected. Also, if "home" is a home with a typical setup of a DSL/cable-modem, etc, etc, you will need to forward the incoming port 80 at the modem to the LAN machine that is your presumed mailserver. I would not do that... I'd get a server from Rackspace for $13/month and do all the testing I want. It is a month-to-month contract. There is a different problem there; Rackspace's policy is to not allow mailservers to run out of arbitrary virtual hosts there. I do it. I get blacklisted and remove the host from the advisory blacklists from time to time. But for testing, it will work fine for you. It will work flawlessly and there are fewer battles to fight. I hope we are of some help. I know you are going to base your business on this, and everything needs to work flawlessly.