I have setup postfix on my server (for my blog to send out emails) however I host my email on google apps. I want my server to be able to send emails towards my GoogleApps account but it's sending it to the user within the system (I know this is normal but I need it to be a bit different).
So you have an application that sends email to "User A" which resides locally and hence postfix delivers as such, locally correct?
If you want to rewrite an email/destination, use the virtual alias table file. Man that or open the /etc/postfix/virtual file and read (postmap it after).
On many systems I have, I do the following: 1. Comment out 'local' in master.cf: #local unix - n n - - local and disable local delivery by editing main.cf to set mydestination equal nothing: mydestination = 2. Edit /etc/postfix/virtual to set: root jcasale@example.com 3. Edit main.cf: virtual_alias_maps = hash:/etc/postfix/virtual local_transport = error:local mail delivery is disabled. 4. Postmap the /etc/postfix/virtual file.
I don't know enough about your setup, but I presume if it's one email you want to redirect, simply do steps 2,3 (not the local_transport part) and 4 while performing the edit on 2 applicably.
You also need to ensure the internet facing side of this server allows smtp outbound and that your server has adequate name resolution. You can use a smart host if you need, post some more detailed info for a less general/possibly wrong answer.
jlc