Hey all, i’ve decided I should probably setup something else to help block nefarious IP addresses. I’ve been looking into CrowdSec and Fail2Ban but i’m not really sure the best one to use.
My setup is OpnSense -> Nginx Proxy Manager -> Servers. I think I need to setup CrowdSec/Fail2Ban on the Nginx Proxy Manager to filter the access logs, then ideally it would setup the blocks on OpnSense - but i’m not sure that can be done?
Any experience in a setup like this? I’ve found a few guides but some of them seem fairly outdated.
Edit: thanks everybody for the great info. General consensus seems to be with crowdsec so I’ll go down that path and see how it goes.
As you probably know the crowdsec bouncer doesn’t directly parse logs or do checks like F2B filters. It queries the crowdsec LAPI for decisions and applies them. The “allowed” or “whitelisted” IP logic is handled at the Security Engine or LAPI level, not by the bouncer itself.
You can whitelist an ip in
/etc/crowdsec/whitelists.yamlor even whitelist decisions in the whitelist.yaml as such:name: private-ips description: Whitelist local and private IPs whitelist: reason: "Allow local and private IPs" ip: - "127.0.0.1" - "192.168.1.0/24" cidr: - "10.0.0.0/8"Then issue
sudo systemctl reload crowdsec. Kind of the same concept as F2B’signoreipoption. If you are using Tailscale to administer the server, then it’s easier to whitelist. IIRC, you can usecscli decisions add --type whitelist --ip 192.168.1.100 --duration 1ybut it doesn’t add them to the whitelist.yaml. Instead it keeps them in crowdsec’s database managed by LAPI. To undo:cscli decisions delete --ip 192.168.1.100 --type whitelisthttps://docs.crowdsec.net/u/getting_started/post_installation/whitelists/
With the bouncer setup, I assume I need to pass in where to look for logs or something for those to be passed into the lapi? I followed this CrowdSec and Nginx Proxy Manager , as far as I can tell everything is connected an running, I have crowdsec running on OpnSense via the plugin - it appears to be healthy as per the CrowdSec Console.
npm | [nginx ] nginx: [error] [lua] crowdsec.lua:62: init(): error loading captcha plugin: no recaptcha site key provided, can't use recaptcha npm | [nginx ] nginx: [error] [lua] ban.lua:37: new(): BAN_TEMPLATE_PATH and REDIRECT_LOCATION variable are empty, will return HTTP 403 for ban decisions npm | [nginx ] nginx: [alert] [lua] crowdsec_openresty.conf:5):11: [Crowdsec] Initialisation done npm | [supervisor ] starting service 'app'... npm | [app ] [5/5/2025] [11:26:30 PM] [Global ] › ℹ info Using Sqlite: /data/database.sqlite npm | [supervisor ] all services started.