I will try an answer you.

Question #1

Yes it typically should be set to the hostname, however it should be set to
the name of the server you set in your dns record under mx.  MX record
specify what computer should receive email for the domain name your using.


Question #2

In your senmail.cf file there is an entry to only allow the receiveing of
mail for the local address of 127.0.0.1

example from sendmail.cf file

# SMTP daemon options

# O DaemonPortOptions=Port=smtp,Addr=127.0.0.1, Name=MTA

So if you comment out that line you should be able to receive email from
mail servers outside of your local net

Jason Lanpher

jlanpher at stealthnetworking.com

http://www.stealthnetworking.com