Is there any way that a milter under postfix can be told that a given client connection attempt failed specifically because of an authentication error?
Sometimes, my email server gets blasted with repeated SMTP authentication attempts from the same client, presumably in order to try to break through my security. I'm running a milter, and these attempts show up as a CONNECT followed by a CLOSE, with an error message in my postfix log that contains info like this:
warning: unknown[aaa.bbb.ccc.ddd]: SASL LOGIN authentication failed: XGFqc3d97mQ6
I'd like to use my milter to track these authentication failures, but I don't know if it's possible for a milter to be notified by postfix that the connection failure is specifically due to an authentication failure.
I can scrape my postfix logs to look for these failures, but I'd prefer to track them via my milter, if at all possible.
Is there any way to do this with a postfix milter?
Thank you in advance.
Well, after a week, I've gotten no responses, and I haven't found any way to make this happen. I will now assume that the answer to my question is "no".