As a hosting provider, we send email on behalf of our clients, so we help them set up DKIM and SPF email records in their DNS to get email deliverability just right. We've been advising them to use http://mail-tester.com to test that they didn't miss anything, and I like this tool a lot.
One problem we've run into a few times, and I'm not sure about, is the DNS "limit" on the SPF record based on domain name. So if you have this:
v=spf1 a include:aspmx.googlemail.com include:campaignmonitor.com include:authsmtp.com include:mail.zendesk.com include:salesforce.com include:_hostedspf.discourse.org ~all
example.com ... campaignmonitor.com: Maximum DNS-interactive term limit (10) exceeded
I have some questions about this.
I count six domain names here, not 10, so why is it hitting "ten" DNS requests here?Answered here Is this 10 DNS interactive term limit a warning or a real error? e.g. should we care? It is nagging our customers a bit and they email us for support.Answered here
Is this 10 DNS interactive term limit a real problem on today's web? As you can see, this customer has a lot of services sending email for them and they are all legitimate. Perhaps this DNS limit was set in the year 2000 when delegating email services like this were not common?
Yes, we can have our customers change the include to IPs in the SPF record but that puts us in a bind if we ever change IPs, a bunch of customers' stuff will break. Really don't want to do that..
What workarounds are there for this?