arp command in Windows: reading the ARP cache and finding duplicate IPs
Before a Windows machine can put a packet on the wire for a host on its own subnet, it needs that host's…
TCP/IP
route print and route add on Windows: read the routing table and make static routes stick
Every packet that leaves a Windows machine is matched against the local IP routing table before anything touches the wire. The table…
tracert and pathping in Windows: reading hop latency and packet loss
tracert maps the routers a packet passes through on the way to a destination, and pathping takes that same hop list and…
Test-NetConnection in Windows: the PowerShell replacement for ping, telnet and tracert
Test-NetConnection is the built-in PowerShell cmdlet that answers the three questions a sysadmin asks when something on the network stops working: can…
netsh command in Windows
netsh (Network Shell) is a command-line scripting utility built into Windows that lets you configure and inspect virtually every aspect of networking…
ipconfig command in Windows: beyond /all
Every Windows administrator knows ipconfig It is usually the first command run when something on the network stops working. But ipconfig…
How to check open ports on Windows: built-in tools vs Port Checker
Checking whether a port is open - on the local machine or on a remote server - comes up in almost every…
NETSTAT command in Windows
When a port is unreachable, a service is not responding, or something is holding a connection open, netstat is the first command…
IP Subnetting Cheat Sheet
Complete IPv4 and IPv6 subnetting reference. Subnet masks, CIDR notation, binary breakdown, private ranges, VLSM examples, and key formulas.