In my set up, ClearOS is not a gateway. It is just a server. And servers have processes that generate mail reports to forward to the admin.
On a more 'normal' server setup, the server may well be in the same domain as all of the other systems, thus this problem. home.htt domain is just a hold over from my setup some 7 - 8 years back.
I think a regular admin, would fall into the same setup I did.
Say Google is hosting your mail service. And you have a Sonicwall gateway (my brother-in-law has a number of clients like this). Then you setup ClearOS as your file/print server and maybe another function or two (local Cloud?). I might think the common thought would be to use your domain name in the mail setup, just as I did. Should be some subzone like smb.foobar.com
Anyway, one more little change. Now all I have to do is either buy one of the cheap OEM copies of Win7 and install it on an old box here, or buy a reconditioned box with Win7 installed. Then I can start testing out an actual client.