4 ms·

You'll definitely lose email from Amazon SES then. What about checking SPF records instead?

• kazinator 10y ago
  My darned residential cable line has forward and reverse DNS that match. If the Amazon SES can't figure this out, they have no business sending SMTP e-mail. I do apply the SPF check and reject the SMTP if it comes up as a confirmed negative: the sending domain has an SPF record, with strict semantics, and the IP doesn't match. SPF speaks to a different problem (not the problem of "is this host a spammy host?"), and generally has no teeth. Passing SPF only informs me that the IP address sending to me is allowed to use the given envelope sender domain. A spammer can register a bunch of domains and set up SPF records for them, and then use the domains as envelope addresses. (Of course, these envelope sender addresses don't necessarily have anything to do with what is in the From: header). You can't expect some sort of free pass just because you made a SPF record. What the SPF record does is protect your domain from being used by other people the bases of a sender envelope address. This is of low value, because most recipients don't even see the envelope address. SPF can be applied against From: too but that's fraught with problems, because of forwarding via mailing lists, or people using alternative sending identities which are legitimate.
• r00fus 10y ago
  Is this a bad thing, if you're trying to avoid spam?