I know that Smartermail's SMTP Blocking allows wildcards in the EHLO Domain, but does it allow for Regular Expressions?
We recently noticed that the EHLO of the majority of spambot networks currently hitting our servers follows the same name format:
(basically three random lower case letters that are common to all servers in that specific botnet, three numbers for the last octet of the server's IP address, followed by the registered domain with a tld that is either .link, .mobi, .me, .pw, or .eu)
Using Regular Expressions I could easily block all of these by adding a STMP Block of:
I suppose I could SMTP Block the EHLO of "*.*.link" and another with "*.*.me" and so on but these wildcards wouldn't be as precise and would block a lot of legitimate Mail Servers.
Does anyone know if SMTP Block EHLO can use Regular Expressions? The documentation doesn't say.