Yahoo FBL confirmation problems

yahoo_en-US_f_p_142x37Over the last few months I’ve seen people complaining about losing the Yahoo FBL emails with verification codes. This seems to be intermittent and no one could really explain what was going on.
Dale Lopez, VP of operations for V12 group, shared that their operations group discovered that one issue with the missing verification emails has to do with the length of the From: address and a port25 default settings.
In Dale’s words:

We figured it out and have confirmed via test. . .  If you are a PowerMTA user (Port25 Solutions), the default from line that PMTA accepts is set to 64. The from line that Yahoo has in the verification code message, is much longer. If you increase the length of the maximum characters to 254, you should receive the verification email.

So if you’re having problems receiving the Yahoo verification emails, check with your IT department to make sure you’re not restricting the path length. The “path” in this case is the return-path address. RFC 5321 says “the maximum total length of a reverse-path or forward-path is 256 octets (including the punctuation and element separators).” Reverse-Path in this case is the address in the envelope from, Forward-Path is the address in the To: line.
So if you’re one of the companies having problems receiving the Y! verification email, check you incoming mail settings and make sure you’re not blocking long email addresses.
 

IPv6 and authentication
Lost in the mists of time

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