legacy hostname problem

["wsykes.lists" <wsykes.lists@deepnines.com>]

All, 

I have a Debian host that used to be called dnimail.
I have since changed the name to mail.
I did this by editing the /etc/host and /etc/hostname file.

when i ping dnimail i get "unknown host dnimail"
when I ping mail i get icmp echos and replies.

the problem is when i try to send mail to a user from using teh command line 
"mail"
 it tries to send the mail to the user@dnimail  which obviously does not 
exist.

I am using postfix, and I double checked the postfix configuration files. None 
of them contain the word dnimail.

I have also stopped and restarted postfix....

Any ideas would be appreciated

thanks 
-William