I'm currently helping a new client with their email setup and I've noticed they have an SPF record configured with a softfail (~all). While it seems okay since emails are passing, this setting allows unauthorized senders to get through, just with a warning. To tighten security, I'm planning to switch to a hard fail (-all), which would effectively block any unauthorized senders. I'm also concerned about their DMARC configuration, as having it set to p=none or not implementing it at all makes the situation worse. This results in unauthorized spoofing of their domain. Once I make the change to -all, I expect to see bounce messages like '550 5.7.0 rejected per SPF policy,' indicating that an IP address isn't recognized as an authorized sender. I'll need to determine if these IPs are from legitimate senders that just weren't added or if they are actually unauthorized attempts to spoof the domain. Does anyone think my plan is solid, or is there anything else I should consider?
3 Answers
I really like your take on this! A good point about the DMARC transition—going from p=none to p=quarantine or p=reject can be a stalling point. Most environments get the reports flowing but don’t actually take action because the raw XML is hard to parse. Using tools like Suped seriously helps in making sense of those reports. It brings clarity to which senders are getting through and which ones are failing, easing the path toward stricter enforcement.
Definitely! It’s all about visibility—knowing what’s really happening with your emails helps in addressing any issues upfront.
Great breakdown of softfail vs hardfail! Some people may argue that only using softfail is the way to go, but that leaves too much room for spam and spoofing. Besides, figuring out an SPF record, even if it's complex, doesn’t take long at all! You’re right to push for hardfail—it’s essential for proper email authentication these days. Just remember to check what else you might need to adjust within your DMARC settings to make sure everything works smoothly together.
Your approach is definitely on point! When you switch to -all, those 550 errors will help identify any rogue IPs trying to send emails. I suggest the first thing to do is pull those flagged IPs from your bounce logs and run a reverse DNS/SPF lookup. This will tell you if they’re legitimate services that just weren’t included in the SPF. If they're valid, you'll want to add them to your SPF record, but keep track of your total DNS lookups—stay under ten! If they turn out to be unknown, it’s best to block them and let DMARC take care of the quarantine or rejection process. Also, before finalizing changes, using an SPF validator is a great idea to catch any syntax errors. Don’t forget to monitor your DMARC reports afterward—this will help you see if legitimate emails are still getting dropped.
Absolutely! Running it through an SPF validator can save you a lot of headaches; syntax issues can cause more problems down the line.
And reviewing DMARC reports will give you a clearer picture of your email flow, helping to catch any legitimate senders that need adjustment.
Right? Parsing those reports is crucial for understanding your email landscape before you push for stricter policies.