We run many scripts on customer servers to email cdrs, backups etc, one problem with some mail servers is the mail gets rejected as it comes from root@elastixserver.yourdomain.com by default to fix this is simple and only takes a few lines.
Postfix MTA offers smtp_generic_maps parameter. You can specify lookup tables that replace local mail addresses by valid Internet addresses when mail leaves the machine via SMTP.
Open your main.cf file
# vi /etc/postfix/main.cf
Append following parameter
smtp_generic_maps = hash:/etc/postfix/generic
Save and close the file. Open /etc/postfix/generic file:
# vi /etc/postfix/generic
Make sure root@elastixserver.yourdomain.com change to elastixserver@yourdomain.com add :
root@elastixserver.yourdomain.com elastixserver@yourdomain.com
Save and close the file. Create or update generic postfix table:
# postmap /etc/postfix/generic
Restart postfix:
# /etc/init.d/postfix restart
When mail is sent to a remote host via SMTP this replaces root@elastixserver.yourdomain.com by elastixserver@yourdomain.com mail address. You can use this trick to replace address with your ISP address if you are connected via local SMTP.
To set up gmail for delivery look at this