An administrator is migrating from iptables to nftables and needs to create a rule that allows inbound SSH traffic on the standard port. Which nft command accomplishes this?

nft insert rule inet filter input tcp dport 22 drop

nft add rule inet filter input tcp dport 22 accept

nft add rule ip filter input tcp sport 22 accept

nft add chain inet filter input tcp dport 22 accept

A Linux administrator is troubleshooting a firewall issue. The server has a rule that allows SSH on port 22, but remote administrators cannot connect. The administrator checks 'iptables -L -n -v' and sees that the SSH rule has a packet count of 0. What is the most likely cause?

A preceding rule in the INPUT chain is dropping or rejecting SSH traffic before it reaches the allow rule.

The default INPUT policy is set to ACCEPT, so the rule is not needed.

The SSH rule is using the wrong protocol, such as UDP instead of TCP.

The SSH service is not running on the server.

CompTIALinux+

Domain 3Objective 2

Firewalls XK0-006 Practice Questions (Page 1)

Part of the Security domain, which accounts for 18% of the XK0-006 exam. CompTIA does not publish an official question count, but from its 90-minute exam (~35–60 total, ~6–11 in this domain), expect 1–2 from this objective — we provide 18 practice questions to prepare you well beyond it. (estimate)

18questions here

4free pages

8concepts

18%of the exam

Questions 1–5

1application · easy
A Linux administrator wants to check the current UFW status, including the default policies and all active rules, in a numbered format. Which command should be used?
Select an answer first
2application · medium
An administrator is migrating from iptables to nftables and needs to create a rule that allows inbound SSH traffic on the standard port. Which nft command accomplishes this?
Select an answer first
3application · medium
A junior administrator used UFW to allow SSH but accidentally blocked all outgoing traffic with 'ufw default deny outgoing'. Users can no longer resolve DNS names. Which command restores outbound DNS resolution while keeping the default deny policy?
Select an answer first
4foundation · easy
Which UFW command enables the firewall and sets it to start automatically at boot?
Select an answer first
5application · medium
A Linux administrator is troubleshooting a firewall issue. The server has a rule that allows SSH on port 22, but remote administrators cannot connect. The administrator checks 'iptables -L -n -v' and sees that the SSH rule has a packet count of 0. What is the most likely cause?
Select an answer first

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Firewalls XK0-006 Practice Questions (Page 1)

Questions 1–5

A Linux administrator wants to check the current UFW status, including the default policies and all active rules, in a numbered format. Which command should be used?

An administrator is migrating from iptables to nftables and needs to create a rule that allows inbound SSH traffic on the standard port. Which nft command accomplishes this?

A junior administrator used UFW to allow SSH but accidentally blocked all outgoing traffic with 'ufw default deny outgoing'. Users can no longer resolve DNS names. Which command restores outbound DNS resolution while keeping the default deny policy?

Which UFW command enables the firewall and sets it to start automatically at boot?

A Linux administrator is troubleshooting a firewall issue. The server has a rule that allows SSH on port 22, but remote administrators cannot connect. The administrator checks 'iptables -L -n -v' and sees that the SSH rule has a packet count of 0. What is the most likely cause?

Keep studying — Security