If for some reason you have a new Basis guy who is looking at things in one of your systems, and he accidentally deletes your SAPconnect host in SICF, here is what you need to do to put it back:
First of all, DON'T PANIC (thank you Douglas Adams)
Go to SICF, hierarchy type "service" and execute
Click the "Create Host/Service" button
Name: SAPconnect
Server Type: SMTP
Host Data
Profile Parameter No.: 0
Host Configuration Information: :
Logon Data
You can leave all as default/blank
Handler List
1: CL_SMTP_EXT_SAPCONNECT
Save
This should get the host back for you to start working with. You will still need to configure SCOT, etc. Also, you should compare this to the way it is configured in one of your other systems to make sure all these settings are correct.
Hope this helps...