I'd like to know how to setup my exim4 on Debian so that it can use gmail as the smarthost, rather than my ISP. It appears to need TLS to be setup, and of course a gmail userid and password. The "standard" smarthost example that comes with exim4 in Debian doesn't have these.
The above solution didn't work for some reason but the solution here worked for me.
http://www.manu-j.com/blog/wordpress-exim4-ubuntu-gmail-smtp/75/
The only change I did was to use xyz@mydomain.com instead of xyz@gmail.com in the “begin authenticators” section.