Question

website and droplet is inaccessible via https and ssh port while droplet is still running

My website is hosted at digitalocean droplet. I use ssh to access the VM. Website uses Cloudflare for CDN. I notice the website is inaccessible via web browser (522 error) and denied new ssh sessions few days ago. I have another PC with an existing ssh session to the droplet. (The PC never shutdown for troubleshooting purposes) I had to stop the firewall (# systemctl stop firewalld) then the website is up and running, and able to access ssh from new session.

After web and ssh is up, I turn on the firewall (# systemctl start firewalld) but the disconnection happenes again after few hours, I had to disable the firewall and it will work again. This just started one month ago. Please help on this.


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alexdo
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December 7, 2023

Heya, @dannyaung

On top of what’s already mentioned there might be a limit to the max concurrent connections to the server, also the already established connections are likely to not be affected by the firewall change until the ssh daemon is restarted.

Hope that this helps!

KFSys
Site Moderator
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December 7, 2023

Heya @dannyaung,

This means the issue is with your firewall. Additionally, the 522 error typically indicates that Cloudflare is unable to establish a TCP connection to your server, which can be caused by a firewall blocking the necessary ports.

When firewalld is running, you should check the existing firewall rules to ensure they’re correctly set up to allow HTTP/HTTPS traffic (ports 80 and 443) and SSH traffic (port 22 by default).

sudo firewall-cmd --list-all
  • Ensure that the rules allow traffic from Cloudflare’s IP ranges. Cloudflare publishes its IP ranges, and you need to allow these IPs to communicate with your server or just allow ports 80 and 443 by default. This list is available on the Cloudflare website. You’ll need to add rules to firewalld to allow traffic from these IPs.

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