Request SPF Records for your Domains
SPF is an anti-forgery technology that everyone needs to use. SPF is a useful tool in the fight against spam. If you want to take advantage of SPF, and your domain(s) use the highspeedrails.com nameservers, please file a support ticket and include the following:
- the domains you want SPF records for
- from where you send email using each of those domains.
If your answer to number 2 is not "only the HSR network", then you need to include a list of all the servers (hostnames or ip addresses) from which you send email using the domain(s) from number 1 above in order for us to establish the SPF record.
More information: SPF Overview from Linux Journal