Here are some quick tips on setting up SPF and DKIM on digitalocean DNS for mandrill transactional email
First, mandrill provides an excellent testing for SPF and DKIM, so use it to see if there are any problems with your current settings.
To get started go to the DNS for your domain
To setup the SPF record choose Add Record
Next choose TXT type
for the name enter: @
for the value enter in quotes:
"v=spf1 include:spf.mandrillapp.com ?all"
you can add additional includes, but do not include your own domain. If you are using another service for your smtp and want to add it, only use the root domain e.g. if your smtp is host701.hostmonster.com only use include:hostmonster.com
click the Create button and you should get a success message
Next lets add the DKIM record. Click Add Record, choose TXT
for the name enter the value: mandrill._domainkey
do not tack on your domain to the end of this, it will not work with the DNS used by digitalocean as it is automatically added.
For the value, enter the key given by mandrill without escaped semicolons, but remember to put the who value in double quotes.
Finally, click Create.
If everything goes well, you should pass both tests on mandrill.