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Host Firewall: firewalld and ufw
Host Firewall: firewalld and ufw A host firewall runs inside the OS: firewalld (RHEL/Amazon Linux) or ufw (Ubuntu). It is a second layer after the security group. Allow only the ports you need. Example (ufw): sudo ufw allow 443 . With firewalld, adding --permanent but forgetting --reload , so the ru
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What it is
A host firewall runs inside the OS: firewalld (RHEL/Amazon Linux) or ufw (Ubuntu).
It is a second layer after the security group.
How it works
Allow only the ports you need. Example (ufw): sudo ufw allow 443.
Common mistake
With firewalld, adding --permanent but forgetting --reload, so the rule never applies.
Without --permanent, the rule is lost after reboot. Use both.
Learn more in the lesson: 32.3 Host Firewall: firewalld and ufw