CompTIA · Linux+ XK0-006
Linux firewalls
Linux+ XK0-006 · Lesson 15 of 28 · 1:56:59
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In this lesson
Prepare for the Linux+ XK0-006 exam (CompTIA Linux+ V8). In this lesson: netfilter, firewalld zones, ports, services, and rich rules (runtime and permanent), ufw, nftables, iptables, and ipset, stateful and stateless filtering, and address translation (NAT, SNAT, DNAT, port forwarding), with Pinecrest Media, a fictional video streaming company, as the running example. Includes three original practice questions.
Preview the topics
- An admin opened port 8443 with firewall-cmd --add-port=8443/tcp, and it worked. After a reboot, the port was closed again. What was missing?
- On an Ubuntu server, SSH must stay open, but an address that tries to connect many times in a few seconds should be blocked. Which command fits?
- Traffic that reaches the gateway on TCP port 2222 must go to the SSH server of a build host inside, on port 22. What does the gateway need?