How to forward email from your VPS to an external email provider

I use Linode to host my domains. I had a need to have an official looking email, and found this post by Jesse Lau. However he is missing a crucial line which I found in this Linode forum post:

virtual_alias_domains = ducklington.org

So the entire correct recipe is:

1. Install postfix

   apt-get update
   apt-get upgrade

   apt-get install postfix

2. /etc/postfix/main.cf download and edit

   virtual_alias_domains = ducklington.org

   virtual_alias_maps = hash:/etc/postfix/virtual

3. /etc/postfix/virtual

   jim@ducklington.org jim@gmail.com
   ted@ducklington.org ted@gmail.com

4. postmap /etc/postfix/virtual to build database

5. /etc/init.d/postfix reload

Some of the chat from the helpful people in the Linode IRC channel may prove of use: