From where do I get the correct syntax to create a proper SPF record for EC2 amazon server? I understand how to create a dns entry but I have no idea what to put in place for the SPF record.
This is very easy to do:
Click here to contact amazon and ask for a reverse dns record for the IP
add the following somewhere in your SPF record and you should be good to go:
a:app-svr-01.youdomain.com
Note: if you need to relay mail through this server from your other AWS servers, or communicate between servers in any other way, you shoukd not use this new FQDN, but rather the AWS FQDN from the AWS console (it will look like ec2-xxx-xxx-xx-xx.compute-1.amazonaws.com).
Using your custom domain name will route through the "WAN" and incur bandwidth charges.