BugBlog

Last days I’ve been busy investigating various email problems. I would like to share a few nice ones with you.

If you start an SMTP session you get a 220 welcomes messages. Which can be one line like:

220 Welcome at our mailserver

Or more lines like:

220-Welcome at our mailserver, we very like te keep spam out of the door and
220 one line is really not enough to put in our crap about policies

The only real thing that matters is that every line starts with 220 and the last one (and only last one) with 220<space>

Now enter the age of cisco-security-by-obsurity-censoring-devices:

(more…)