Antispam whitelist

There is always plenty of talk about how good or bad a blacklist, or blocklist, is with comments about the false positives generated by that list. These days, with spam at approx 96% of the total daily volume of email sent, no sane email Administrator would operate email servers without first using a whitelist and thereafter possibly filters in addition.

I have had excellent results from these guys;
http://www.whitelisted.org/
You may want to get your own email server listed on their database so that your emails have a better chance of successful delivery, see their website for instructions. The whitelist service seems to be associated with, or run by, http://wwwUCEProtect.net/ , a German blacklist operator.

UCEProtect actually have 3 main blacklists each with it's own listing criteria. Using all 3 blacklists together on your email server will require 3 blacklist entries for DNS lookups but the combined results are very close with those of L2.APEWS.ORG. UCEProtect.net may provide better results for European language based senders and receivers, results here suggest that APEWS.ORG data is particularly good for English.

The use of a whitelist is to exempt the need for blacklist checking, i.e. it is a list of trusted IP addresses. Any sender of an email from a whitelisted IP address can be trusted to connect and deliver their email without any further checking. There can not be any error due to a blacklist since one has not been consulted!

Any connecting IP address that is not whitelisted probably can not be trusted and therefore warrants further checking. Things like PTR records can be useful indicators but as mentioned previously, we see email service providers to governments using badly configured email servers where the reverse DNS does not match. Results here suggest to ignore PTR record checking and just do a blacklist DNS lookup, creating X-Headers for those connecting IP addresses that are blacklisted.

False positives can be seen to be a reflection of the quality of the whitelist being used. If the whitelist maintainer has their data accurate, it would not matter whether trusted email servers were listed in the blacklist or not. Fine tuning of data for both whitelists and blacklists is a coninuous job though once the bulk of the entries are in it is just a matter of adding the odd one at local level.