A quick search for one of the IPs shows this: https://www.abuseipdb.com/check/46.148.40.161
So yes, it's most likely an attack.
A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.
For Example
We welcome posts that include suggestions for good self-hosted alternatives to popular online services, how they are better, or how they give back control of your data. Also include hints and tips for less technical readers.
Useful Lists
A quick search for one of the IPs shows this: https://www.abuseipdb.com/check/46.148.40.161
So yes, it's most likely an attack.
Yeah that looks a lot like the typical bruteforce attempts from the evil lands of the internet. Fail2ban did the trick for me. Logs are clean now
If there's one thing I've learned over the years about self-hosting it's that I'll happily pay to not have to deal with email hosting.
The only "self-hosting" I do for email is to download my own local archive for storage.
It's not a big deal to me and I'd rather have control over the services and, more importantly, the data. And my rented server is cheap.