inconsistent results about check-if-email-exists

[tyranron]

@rxng with the latest #819, #822 and #825 fixes it should be much better now.

Also, consider the fact that the checking performed is nothing but a half-way delivery attempt. So results will really vary depending on the IP you're performing the check from and on from-email parameter, because SMTP servers considers rDNS records, SPF DNS records and IP reputation, where the last one especially changes over time.

So, to have good and consistent results, you should properly setup DNS stuff on the server you're performing checks from, and care about its reputation.

[amaury1093]

Hmm, yes, "unknown" can be understandable, but the "safe"/"invalid" one does look bad. Could you send me the email you used, to [email protected]? I'll do some debugging on my side.

This issue should be top on the priority list.

Note: if you want to debug it yourself, the best way would be to run with RUST_LOG=debug env variable, and check the SMTP commands and their responses.

[amaury1093]

I'm going to close this issue, since the 3 PRs mentioned by @tyranron have been merged. Thanks everyone for looking into this!