Thank you for suggesting the region block on Unifi, that’s a good tip.

I have that previously set in place globally under settings -> security -> protection -> region blocking.
So on a less sophisticated level and not as granular as you.
Yours seems to be much better and I will take a look at it later. At the moment I have way too many ideas and projects boiling, to add yet another one… ;)

Thanks for bringing it up.

Before I dove into that project, I was checking logs on npm and the service I am already exposing. It seems to me, both only get http GET requests which on npm all get a 404 response.
I don’t remember what the service does with those, but I will investigate later. As I didn’t panicked, I guess it wasn’t that bad.

There are basically no brute force attacks on the service yet and the admin account is only allowed to login from internal IPs.

One initial aspect to further harden the exposed systems were the logs in the UDM which show frequent blocked attempts of varying severity.
This may be security theater and I am not able to assess whether the UDM is a “good enough” protection of the most common attacks.

As I see it, at the moment the UDM already blocks most of the (more sophisticated) attacks and leaves only common requests for the services to handle.

Long story short, as I see it, the UDM has the role of ingress server in my setup.

Thank you very much for your input. I will look into the third option.
Thought of it, but did forget it over tinkering the last few days. :)

As you say, “at the time, a reasonable decision”. What I don’t understand tho, is, why nobody, for five seconds, maybe thought, how it could be a good idea to just filter this standard address at the SMTP server to be redirected to something sensible inside the org. My best guess is, different departments / sub orgs.

I enjoy apalrd very much, down to earth, deep dive, no bullshit explanatory videos mostly about networking.

I don’t know about torrent downloads, but for “obviously illegal” streaming and IPTV offerings, customers also will get bonked. For example [German]: https://www.bms-rechtsanwaelte.de/wirtschaftsrecht-blog/illegales-iptv-streaming-strafbarkeit-nutzer

Hi, could you tell me why? I mean, I think I understand the basics of the risk of brute force attacks. My mitigation for the admin account is, not to allow login outside the local network. Users are allowed from anywhere, as my family uses the library. Also my service (there are others) are routed through NGINX.

Do you have tips for external users using, for example, a VPN only for specific addresses / IPs? At least that was an idea I had, but didn’t got got around to dig for solutions.

Thanks in advance.