sendmail help

[Denys Vlasenko]

On Wednesday 25 February 2009 07:18:23 am Vladimir Dronnikov wrote:
> Hi, Frank!
> 
> 2009/2/25 Frank Ianella <fjianella at gmail.com>:
> > i am trying to use the sendmail applet to relay to smtp.gmail.com but
> > cannot figure out the neccessary command syntax.
> >
> 
> You can try working:
> $ sendmail -H "exec openssl s_client -quiet -connect smtp.gmail.com:25
> -tls1 -starttls smtp" -f user at gmail.com -F "Your real name here (pure
> optional)"

Is it possible to use port 465? Port 25 sometimes is blocked by ISPs.

> You'll be prompted for password, or you can pass you credentials (two
> lines file: username, password) to fd 4 like:
> $ sendmail -H "exec openssl s_client -quiet -connect smtp.gmail.com:25
> -tls1 -starttls smtp" -f user at gmail.com -F "Your real name here (pure
> optional)" 4<.your_cred_file
> 
> Notice "exec, -quiet, no -crlf and -tls1".

Why username/password is passed through fd 4? I don't see where that happens.
Is it a openssl's feature? I tried to google for that but so far failed.
--
vda