If you have a dedicated IP, you can instruct your clients or recipients to add just that IP to their safelist (which may also be called a whitelist). If you do not have a dedicated IP, your emails will be sent from Transactional Email's shared IP range. This range is continuously updated as we add more servers for sending.
We do not recommend adding IP addresses to safelists because Transactional Email's shared IPs may change without notice and the recipient would be adding all mail from Transactional Email to the safelist. If safelisting by IP is the only option, the recipient domain should check for the most up-to-date IP information in the TXT record for spf.mandrillapp.com. On a Mac or Linux, use the following command to get this information:
dig TXT spf.mandrillapp.com
The record is updated when new IPs are added to Transactional Email's sending IP range. If a receiving server is safelisting the range, we recommended periodic checks to ensure they have the current range used by Transactional Email.