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  • You're amazing, thanks for the comment. It really helped me to better understand the situation. I have one question about no-ip use. For example, I have it set in my house to log in server and send emails, I still can send emails out of my house, but I can't do a ssh in server. In this case, I don't need an include statement in SPF, right? I have the no-ip include for this reason, but it doesn't seem to be needed. Commented yesterday
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    If your no-ip.com usage is limited to dynamic DNS (for example, to reach your home server via SSH) and no mail is being sent through infrastructure operated by no-ip.com, then that include is likely unnecessary. Their SPF record applies only to their email infrastructure and will not authorize IP addresses registered with their dynamic DNS services. This therefore appears to be a candidate for removal. Commented yesterday
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    Dynamic IP addresses generally should not be used directly for sending email. If your home server sends mail, it should normally relay either through your own properly configured mail server with a static IP address or through an external mail provider, and only that infrastructure needs to be authorized in SPF. Commented yesterday
  • I am glad the answer helped you better understand the situation. That was also the intent behind focusing on general concepts rather than provider-specific details, aiming to explain the underlying principles instead of only providing a one-off fix. The goal was to provide an analysis method that you can apply to your own infrastructure, and that others encountering similar SPF lookup issues can apply to their own use cases. Commented yesterday
  • Concur - 10 is the hard limit on a lot of systems, and other domain names wildly ignore it. Toyota.com was famous for having 18 for a long time, but now theirs is down to 6, each of which is a long string of IP blocks with no further lookups. Commented 20 hours ago