Spam level headers in Thunderbird

Spamassassin adds several special headers to every email that it scans. One of these is X-Spam-Level, that is, the degree of “spaminess” that the email scored.


When training your spam filters, it can be useful to see the score of each scanned email. In Thunderbird, this can easily be done by changing a setting using the config editor. In the field mailnews.headers.extraExpandedHeaders add the value X-Spam-Level.


As a bonus, to see the user agent string, you can also use the config editor by setting mailnews.headers.showUserAgent to value true. This simple flag renders a separate plugin for this functionality superfluous.

Gmail-style email address aliases with Postfix

As some might know, Google offers alternative ways to refer to Gmail email addresses.

For example, you can use the “plus” technique to make distinctions between different organizations that you share you email address with. For instance, if you own, then example+nospam still delivers to the same address. Indeed, everything after the plus symbol is ignored (Gmail is simply adhering to the standard here).

One advantage of this technique is that you can hand out different email aliases to different organizations. If you start receiving spam on any of these aliases then you can trace this back to the organization which leaked your email address to spammers.

The Postfix mail transfer agent also supports such a feature. If you set

recipient_delimiter = +

then Postfix tries to deliver to example+nospam, and if this doesn’t exist, will deliver to example.

Of course, you can change this parameter. This is especially interesting if you own the whole domain name and do not need to consider other users. Changing the parameter to a dot symbol is not a bad idea, since many web forms tend to inadvertently block out the plus symbol.