Windows
What built-in Windows feature filters network traffic to help prevent unauthorized connections?
Windows Defender Firewall
What command displays the username of the current terminal user?
whoami
What does an IP address identify on a network?
A network interface or device's logical network address
What command-line utility can test whether another host is reachable using ICMP echo requests?
ping
What Windows tool can you use to view and manage local user accounts and their group memberships on supported editions?
Computer Management → Local Users and Groups
What command checks whether the UFW firewall is active?
sudo ufw status
What is the purpose of a subnet mask?
It identifies which part of an IP address represents the network and which part represents the host.
What is the default port for HTTPS?
TCP port 443
What is the purpose of a firewall on a Windows or Linux computer?
To filter network traffic according to security rules.
What PowerShell command lists local user accounts?
Get-LocalUser
What command lists user accounts from the system's account database?
getent passwd
What does the default gateway do?
It forwards traffic from the local network to other networks
What is the difference between TCP and UDP?
TCP provides reliable, ordered delivery; UDP sends datagrams without guaranteeing delivery or order
A computer can reach 8.8.8.8 by IP address but cannot open websites by domain name. What should you investigate first?
DNS configuration and name resolution
What Windows management console can configure password policies and account lockout policies on supported systems?
Local Security Policy (secpol.msc)
What command checks the status of the SSH service on a system using systemd?
systemctl status ssh
What is the difference between a private IP address and a public IP address?
Private IP addresses are used within private networks and aren't directly routed across the public internet. Public IP addresses are globally routable
What protocol automatically assigns IP addresses and other network configuration to devices?
DHCP
A computer has an IP address of 169.254.10.20. What might this indicate on a typical network?
It may have assigned itself an APIPA/link-local address because it couldn't obtain an IPv4 address from DHCP
You find an unfamiliar account in the Administrators group. What should you investigate before removing it?
Check the README, authorized-user requirements, account purpose, and group memberships. Confirm it is unauthorized before making changes
A user is in the sudo group but shouldn't have administrative privileges. What should you check before changing their access?
Verify the README and authorized-user list, confirm the user's role, and investigate other privilege-granting mechanisms
A computer has IP address 192.168.1.25/24. Is 192.168.1.80 on the same subnet, and why?
Yes. Both addresses belong to the 192.168.1.0/24 network
What are the default ports for SSH, DNS, and HTTP, respectively?
SSH: TCP 22; DNS: port 53, usually UDP or TCP; HTTP: TCP 80.
A computer can communicate with other devices on its local subnet but cannot reach an external IP address. Name two configuration issues you should investigate.
The default gateway and subnet configuration are two possibilities; also check routing, firewall rules, and network connectivity.