I’ve tried it with the following blacklist domain:
\d+\d\d\d.\w+
which should match any domain which is made up of four or more numbers (and numbers only).
I checked the setting with Data Explorer and confirms that email_domains_blacklist is mailinator.com|cc|\d+\d\d\d.\w+, which is correct.
The code regexp = Regexp.new("@(.+\.)?(#{domains})", true) should now filter off emails coming from domains with long digits.
EDIT: Note: not sure what the second parameter true is doing in a call to Regexp.new(), which takes as a second parameter the matching options.
However, I just had three new SPAMmers came through:
ddef@445555.com
mnopp@89990001.com
gg5@996399.net
So obviously it is not working.
Trying the RegExp in a JavaScript console confirms that it works:
/@(.+\.)?(mailinator\.com|cc|\d+\d\d\d\.\w+)/.test("ddef@445555.com")
true
There, the domain blacklist is not working as it should.