Linux+ Networking Services and Protocols Flashcards

Which firewall management daemon uses zones to control traffic and serves as a front-end for nftables on many modern Linux distributions?

Answer: firewalld

firewalld is a dynamic firewall daemon that manages nftables/iptables rules using zone-based policies and supports runtime and permanent rule changes.

What does the command `scp report.txt admin@192.168.1.10:/var/log/` accomplish?

Answer: Securely copies report.txt to /var/log/ on the remote host over SSH

scp (Secure Copy Protocol) transfers files between hosts encrypted over SSH using the syntax: source destination.

Which file controls the order in which name resolution sources (files, DNS, etc.) are queried on a Linux system?

Answer: /etc/nsswitch.conf

/etc/nsswitch.conf (Name Service Switch) defines the lookup order for databases such as hostname resolution, users, and groups.

Which command sends ICMP echo requests to a host to test basic network reachability?

Answer: ping

ping sends ICMP echo request packets to a target and reports round-trip time, confirming whether the host is reachable at the IP layer.

Which firewall-cmd option ensures that a newly added rule survives a system reboot?

Answer: --permanent

The --permanent flag writes the firewall rule to the permanent configuration so it is restored after a reboot or firewalld reload.

Which directive in /etc/ssh/sshd_config restricts SSH access to a named list of users?

Answer: AllowUsers

AllowUsers in sshd_config specifies a whitelist of usernames permitted to log in via SSH; all other users are denied.

Which command displays the route packets take from the local host to a destination, showing each intermediate hop?

Answer: traceroute

traceroute sends packets with incrementing TTL values to reveal each router hop between the source and the destination.