Securing cloudron against ddos attacks?

[humpty]

@girish would adding an OPNsense firewall to a Cloudron home server cause any issues (assuming all needed ports are opened like what was done in the router)?

[necrevistonnezr]

@lukas Crowdsec could be an option: https://forum.cloudron.io/topic/6224/crowdsec-install-guide-for-cloudron-purposes/1?_=1682161029208
Though I don’t know what’s the status of it and its compatibility with Cloudron…

[jadudm]

@humptydumpty I run OPNsense in front of Cloudron. I'm not doing anything fancy with it, but it does live between the world and my self-hosted Cloudron instance.

I have no idea what would happen if the machine was DDoS'd. I'm pretty sure it would fall over. At this point, I'm just excited that I have cron'd backups locally and to offsite.

[humpty]

@jadudm That’s great. Thank you!

[lukas]

@necrevistonnezr said in Securing cloudron against ddos attacks?:

@lukas Crowdsec could be an option: https://forum.cloudron.io/topic/6224/crowdsec-install-guide-for-cloudron-purposes/1?_=1682161029208
Though I don’t know what’s the status of it and its compatibility with Cloudron…

@girish maybe you guys can implement this into cloudron?

[girish]

@jadudm said in Securing cloudron against ddos attacks?:

@humptydumpty I run OPNsense in front of Cloudron. I'm not doing anything fancy with it, but it does live between the world and my self-hosted Cloudron instance.

Do you have any specific rules on OPNsense for DDoS?

@lukas @humptydumpty Cloudron already has a very restrictive firewall. All ports are closed other than http and https (unless an app needs them). Email ports are opened dynamically and only if email server is enabled. There's also rate limits in place for things. With DDoS, it's a power battle though between the Cloudron CPU and the bots army. For tackling a real DDoS, one needs to receive requests over multiple physical/server regions. i.e the bot requests are first "processed" in the region where the bot resides. They do this with so called anycast IP addresses (single IP on multiple servers and assistance from DNS).

[humpty]

@girish that’s great to know but I’m adding opnsense for non Cloudron related reasons. My router sucks and I want to have more control over my network but didn’t want to go through the trouble only to have it choke my home server connection.

[jadudm]

@girish No, I don't think I have any particular DDoS protection configured in OPNsense. However, this conversation makes me curious to investigate it.

I run the DNS through Cloudflare, which... may or may not provide me with some protection. (I'm not being cagey, so much as haven't really dug in to understand how/if Cloudflare protects my Cloudron domain/subdomains.)

I'm happy to experiment with OPNsense configuration, if it's a space of question. However, it serves more for internal protection than external (at the moment). I mostly use it to partition the Cloudron machine off from the rest of the house via VLAN as a "just-in-case" measure. It keeps Cloudron separate from dumb internet lightbulbs, which I consider a kind of mutual protection.

[LoudLemur]

Like Hetzner, Contabo also offers DDoS protection:
https://contabo.com/en/ddos-protection/#what-are-the-limits-of-contabo-ddos-protection

From Claude AI:

Here are a few key points comparing layer 7 and layer 4 DDoS mitigation for protecting websites that stream audio/video:

Layer 7 (application layer) DDoS protection can detect and mitigate more sophisticated application-layer attacks that target weaknesses in the web application code, such as HTTP floods, low and slow attacks, and exploits that abuse APIs.

Layer 4 (transport layer) DDoS protection focuses on network and volumetric attacks like UDP and ICMP floods which aim to consume bandwidth and overload infrastructure.

For streaming websites, a hybrid approach providing both layer 4 and 7 mitigation is recommended. Layer 4 protects against bandwidth-exhaustion attacks while layer 7 covers exploits at the application layer.

Top providers known for DDoS protection services include Cloudflare, Akamai, Imperva, F5 Networks, and Radware. Specific solutions include:

Cloudflare Magic Transit and Spectrum
Akamai Prolexic Routed
Imperva Advanced DDoS Protection
F5 Silverline
Radware DefensePro
Features like behavioral analysis, per-client throttling, SSL decryption, and integration with CDNs and DNS services make these robust protections against network and app-layer DDoS attacks.

In summary, combining layer 4 and 7 DDoS mitigation from a reputable provider gives streaming sites the best protection against volumetric bandwidth attacks and application exploits. Cloudflare, Akamai, and Imperva are leaders in the space

[IniBudi]

@loudlemur hmm my server's just hit by DDoS and it consumed 1TB bandwidth. If we only use Cloudflare free and VPS that has anti DDoS feature (like Hetzner or Netcup) but the server still down. Is there effective way to mitigate this situation?

[LoudLemur]

@IniBudi I am not sure, but according to Grok:

"you've got a classic volumetric DDoS (the kind that floods bandwidth with junk traffic like UDP floods or SYN floods) that chewed through 1TB and knocked your server offline. Cloudflare free + Hetzner/Netcup anti-DDoS is a solid starter setup, but it's getting bypassed or overwhelmed because:Most attacks hit your VPS's real IP directly (bypassing Cloudflare unless everything is perfectly proxied).
Hetzner's protection (Arbor/Juniper-based) is automated but often slow to kick in or just null-routes your IP (blackholes the whole server to protect their network). Netcup's 2 Tbps filter is better but still leaks big attacks or causes brief downtime.
Cloudflare free is unmetered and excellent for web traffic routed through it (absorbs massive attacks at the edge), but it only helps if traffic never reaches your VPS.

The 1TB bandwidth bill/spike proves the attack was hitting your origin directly.Immediate Effective Fixes (Do These Right Now — Mostly Free)Force everything through Cloudflare
In Cloudflare DNS, make ALL records Proxied (orange cloud icon). No A/AAAA records pointing directly to your VPS IP. This routes attacks to Cloudflare's global network first.
Lock your VPS firewall to Cloudflare IPs only (this is the #1 game-changer)
Block everything except Cloudflare's published IP ranges. This stops 99% of direct IP attacks. Hetzner: Use their Cloud Firewall (or iptables).
Netcup: Same with ufw/iptables.
Cloudflare publishes the list here: cloudflare.com/ips (update it automatically via their API — there's a simple cron script for this).
Result: Attack traffic dies at Cloudflare; your VPS barely sees clean traffic.

Activate Cloudflare's emergency mode Turn on "I'm Under Attack" mode (Security → Overview).
Enable Bot Fight Mode + managed WAF rules + rate limiting (free tier has these).
Set Security Level to "High" or "I'm Under Attack".
This challenges suspicious traffic with JS/captchas before it even reaches your server.

Extra quick wins Use Cloudflare Tunnel (cloudflared) if possible — runs on your VPS and proxies traffic without exposing any ports publicly. Zero public IP exposure.
On the server: iptables rate limiting + fail2ban for extra layers.
Contact your VPS support immediately — they can sometimes manually tune mitigation.

These steps alone usually stop the bandwidth massacre because Cloudflare absorbs the junk at their edge (they've mitigated 11+ Tbps attacks).The Strongest Solutions (Ranked by Effectiveness vs Cost)Here's what actually survives big attacks in 2026:Best affordable strong solution: Switch VPS to OVHcloud + keep Cloudflare free/Pro
OVH has the strongest built-in, always-on DDoS protection in the budget VPS world (unlimited, multi-Tbps scrubbing centers, rarely null-routes, works great for L3/L4 volumetric). Users consistently report it handles attacks that destroy Hetzner/Netcup. Pair it with Cloudflare for L7 (web) protection and you're basically bulletproof for most attacks. Migration is straightforward (snapshot your server, spin up OVH VPS, point DNS). This is the combo I recommend for 90% of people in your spot.
Specialized DDoS-protected hosting DDoS-Guard (or similar like PATH.net / Evolution Host): Purpose-built for heavy volumetric attacks. Offers protected VPS or proxy services with fixed pricing and excellent filtering. Great if you want to stay cheap but stronger than Hetzner/Netcup.
BuyVM: Super cheap add-on protection (handles 700M+ pps).

Upgrade Cloudflare only (if you love your current VPS)
Go Pro ($20/mo) for advanced WAF, better rate limiting, and more rules. Still use the firewall lockdown above. For non-HTTP/UDP (games, APIs, etc.), you'll eventually need Cloudflare Spectrum (paid) or a dedicated L4 protector.
Enterprise-level (if budget allows and attacks are constant)
Cloudflare Magic Transit (BGP routing) + your VPS, or Akamai/Imperva. These are what big sites use — full network scrubbing.

Quick Reality CheckIf your server is a website/API (HTTP/HTTPS), the Cloudflare + firewall lockdown + OVH combo will solve 95% of cases for very low cost.
If it's a game server, UDP-heavy service, or Minecraft/etc., prioritize a host with native L4 protection (OVH or specialized like TCPShield) — Cloudflare free alone won't proxy those ports easily.The core principle for any strong solution: You need high-capacity upstream scrubbing so the 1TB flood never reaches your VPS bandwidth/CPU.Do the immediate firewall + proxy steps first — that often fixes it instantly without spending anything. If you tell me exactly what your server runs (website? game? API? ports?), attack type (from CF analytics), or your budget, I can give exact config commands/scripts or migration steps.

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