There are two configurations to do to use RealSender:

1. Change the settings of the outgoing mail (SMTP) within your email client:
   Outlook - Outlook 2007 - Mac OS/X Mail - Thunderbird
    
2. Optional (allows you to authenticate messages sent with SPF and DKIM): 
   add a few lines to the DNS records of your domain name
   (requires max 5 minutes to your domain name provider)
   
   after we setup your RealSender account, we will send you an email asking
   to add these records to the DNS settings of your domain name:
   yourdomain.com. IN TXT "v=spf1 ip4:123.123.123.123 ~all"
   yourdomain._domainkey.yourdomain.com. IN TXT "k=rsa; t=y; p=..."
   
   All these changes can be easily verified online.
   Once we receive the confirmation that the changes have been done,
   we'll check them and let you know that everything's ok.

The number of recipients for each piece of email is limited to 25.
If you need more, please look at "Newsletter software" area.