One of the advantages of running my own MDaemon server is that I keep an eye on a lot of the spam and abuse that’s floating around on the internet.
Over the years I’ve put together a list of EHLO strings that can be used by MDaemon’s host screening tool to block inbound connections. Most of these are invalid based on their syntax, but yet are hitting a reasonable number of spam delivery attempts. Find the HostScreen.dat file \MDaemon\App directory and add the following:
all localhost refuse
all user refuse
all friend refuse
all -* refuse
all *_* refuse
all #.#.#.# refuse
all *.invalid refuse
all *# refuse
all */* refuse
all *|* refuse
all ylmf-pc refuse
Save the file, and then create a “hostscreen.sem” in the \MDaemon\App directory to reload the contents of the HostScreen.dat file.
If you haven’t used MDaemon’s semaphore (SEM) files before, the following command will do it:
echo. > C:\MDaemon\App\hostscreen.sem
I have yet to observe any false positives, although it’s not impossible, so watch your logs if you’re worried.
I do periodically update this list, and if anyone has any entries to contribute, please do so in the comments. When the post is updated, it will be promoted to the top of the list, but generally no email notifications will be sent.