Check iptables, ufw or firewalld, then your Vultr Firewall Group, since either layer can block traffic.
If you're experiencing connection issues with your Vultr Compute instance, the problem may be due to a misconfigured firewall. Misconfigured rules can prevent your server from accepting incoming or initiating outgoing traffic. On Vultr you can configure instance level firewall or a Firewall Group:
iptables, ufw, or firewalld, configured directly on the OS.Check both layers to diagnose and resolve connectivity issues.
Vultr instances running Linux have iptables installed by default. To check if any firewall rules are active, run:
No Active Rules (Firewall Not Filtering Traffic)
If the output is like this, your instance is not blocking any connections at the OS level. In this case, check your Vultr Firewall Group settings.
Active Rules (Firewall Filtering Traffic)
If the policy is DROP or certain ports are explicitly allowed, then filtering is active. Proceed to inspect using UFW or FirewallD.
If you're using conflicting firewall rules and need to reset:
And for IPv6:
These commands fully disable filtering; use with caution.
If your instance uses UFW (common on Ubuntu), run:
Sample Output:
This means only the listed ports (e.g., 22, 80, 443, 3001) are allowed, and all other incoming connections are denied by default.
If you want to disable UFW temporarily:
Only disable UFW if you have Console access to recover SSH.
You can modify UFW rules to match your application's needs using:
Some Linux distributions (CentOS, Rocky, AlmaLinux) use firewalld.
Check the firewalld status.
If running, list active zones:
List rules in a zone:
Stop and disable firewalld if needed:
If your instance is attached to a Vultr Firewall Group:
22/tcp for SSH) are open.Vultr Firewall Groups use a default-deny policy. If a specific port or protocol is not explicitly allowed in the inbound rules, all traffic on that port will be blocked.
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