The quest to avoid SMTP Hacking and "Authentication Failed" on Domino-server continues

Tags: Lotus Domino Configuration

Update Nov, 11th, 2017: If your are using the sample database, you need a configuration first. Go to the configuration-view and press the "Configuration" button to create one.


This blog-post is about a combination of my own agent creating an IP-address list and a product named "IP Blocker". The combination automatically pumps bad IP addresses from Domino log to IP Blocker – and gone are the bad IP address.

Even though I have some sort of control on the numerous SMTP hacking attempts happening every day, I still feel uncomfortable just seeing that they keep on pounding my server. What do I mean?

The log gets lots of messages like this;

07.11.2017 05:00:06   SMTP Server: Authentication failed for user stevens ; connecting host

Back in March 2017 I wrote the blog-post Finally I managed to stop the SMTP hacking, generating tons of "SMTP Server: Authentication failed for user ..."-messages. Back then I was using the Windows Firewall to trap the bad IP addresses, and that worked. Every IP address registered was effectively blocked from ever reaching my server. The down-side was to keep up with all the new IP addresses, and somewhat cumbersome user interface to register IP addresses. My blog post goes into detail how that was done.

A reader named David Brown commented on the blog-post and referred to his blog-post Disable SMTP-AUTH To Stop Relay Hackers In Their Tracks, which suggested the somewhat strange tip to turn off the SMTP Authentication server in order to actually automatically fence out the bad IP addresses.

Here the other day I came across another Windows tool named IP Blocker from BeeThink-software. It looks a little outdated, but it turned out to be quite powerful! Below you see it in action on my Windows machine;


All the red dots are blocked addresses! What was the most important selling point to me was the ability to automatically load IP-address lists.

What if I created an agent retrieving all the "Authentication Failed" messages, extracting the IP addresses and automatically created an IP-address list file to IP Blockere to read?

Read on to meet "Authentication Failed Extractor" database Smile