I wanted to let you know that I have a new site and a brand new email whitelist generator here:

http://www.emaildeliveryjedi.com/email-whitelist.php

I have so much conflicting content that I have to divide the two blogs so the email stuff went to email jedi.

I have completely retooled the app and now it has even more instructions like blackberries and SpamCop (yeah spam cop has a whitelist).

Any links of comments on this would be appreciated.

- Chris

I am happy to report that Yahoo no longer seems to be rejecting emails sent from PBL-listed IP addresses (PBL-Public Policy List). Those emails now seem to be pushed straight into the spam folder, probably without being processed by spam filters, instead of being rejected outright. How do I know that? I have received 2 100% non-spam emails in my spam folder in the last 24 hours and they were both listed in PBL and PBL only.

Hoping that this is a permanent policy change on Yahoo’s part.

I would advise anyone with a Yahoo email account to regularly monitor their spam folder in case there is a good email stuck somewhere in it.

1) are you using a NAT and is the blocked IP actually the NAT IP?

2) Is it possible that IP being blocked is an open proxy?

Without the IP I can’t help you troubleshoot it any further, but those are where I would start. The full list of things to do is on the Yahoo postmaster page at: http://help.yahoo.com/l/us/yahoo/mail/postmaster/postmaster-26.html

We’re getting this right now. We’re not anyone’s black hole list. I checked. Nor do we fail the open relay test. The email address that you see above is my personal yahoo email addy. The email that was sent was sent from my personal work email addy. The email that was sent said “Test to see I can get this”.

JFC!!! We’re an educational institution!!!!! We’re not spamming anyone.

I do understand your point and I believe there are some Yahoo folks reading this blog. I can only posit that their testing shows that for mail incoming to Yahoo their statistics show something completely different.

If using the PBL is problematic for them, and blocks more real mail than they believe their users will put up with, then I expect to see them drop it.

In both cases above, the marking of non-spam emails as spam becomes virtually inevitable when using blocklists such as Spamhaus’ PBL which lists millions of IP addresses used by customers of large telecom companies and ISPs.

Our 6% FP-False Positives rate for PBL comes from real-life filtering for hundreds of user mailboxes, unlike some statistics generated in artificial environments that have no users other than the site’s owner (e.g. dnsbl.com).

One can only hope Yahoo will come to its senses and stop its use of non-precise blocklists such as Spamhaus’ PBL if it wants to reduce the number of legitimate emails that are bound to be wrongly rejected as a result of consulting those blocklists. Or it may find its customer base change allegiance to more reliable services that do not blindly reject emails at the perimeter.

False positives in a list like PBL come in two flavors:

1. Oops, that IP isn’t dynamic. Oops, we do have MTAs in that space. Oopses, mostly. PBL is good about addressing those. They even have self-removal.

2. Servers disallowed by ISP policy.

Those latter ones start religious wars. If you want to accept mail from IPs that shouldn’t be sending mail as defined by the policy of the IP address owner, more power to you. But you can’t use any sort of PBL or any dynamic-blocking list.

I think FPs from #2 are really only a tiny subset of guys running Linux boxes in their basement. Frankly, I’m okay with not receiving that mail.

I’d love to see Alex’s stats, because at face value, I don’t see how it’s even possible for PBL to block 6% of legitimate mail. I’m just not buying it.

Quoting Al Iverson (http://www.dnsbl.com/2007/10/spamhaus-zen.html): “I would always recommend that before using Spamhaus ZEN, or any other blacklist, that you test and investigate on your own, to make sure that you are comfortable with the blacklist provider’s policies.” Good advice which you’d think large email hosters such as Yahoo would heed before starting to deploy *any* blocklist for their millions of users.