This is tangental, but while we're talking about SPF... I've noticed lately that it's getting trickier for businesses to stay within the 10 DNS lookups per SPF

This is tangental, but while we're talking about SPF... I've noticed lately that it's getting trickier for businesses to stay within the 10 DNS lookups per SPF record limit. For example, Google's official SPF record is _spf.google.com which in turn includes _netblocks.google.com, _netblocks2.google.com and _netblocks3.google.com. That's 4 DNS lookups. Use Salesforce? They include Google's SPF record in theirs. Use Zendesk? Their previously published SPF records are support.zendesk.com and smtp.zendesk.com. Both those record include mail.zendesk.com which includes _spf.zdsys.com which includes _netblocks.zdsys.com. The number of includes/DNS lookups is a growing problem as these businesses continue adding more IPs. If you're allowing several external services to send email on your behalf, you might want to double check your SPF record to see how many DNS requests you're making.