networking

Common networking commands for interfaces, ports, DNS, routing, firewalls and connectivity troubleshooting.

AllLinuxmacOSWindows

Most Used

Start here for local network details, open ports and connection failures.

Show network interfaces and local IP addresses

Identify network interfaces and the IP addresses assigned to them.

macOS

scutil --nwi

Pretty print

ifconfig | awk '/^[a-zA-Z0-9]/ { iface=$1; sub(/:$/, "", iface) } /inet / { print iface, $2 } /inet6 / && $2 !~ /^fe80:/ { print iface, $2 }'

Linux

ip -brief address show up

Pretty print

ip -brief address show up | awk '{ for (i=3; i<=NF; i++) if ($i ~ /^[0-9a-fA-F:.]+\/[0-9]+$/) print $1, $i }'

Windows

ipconfig

Pretty print

Get-NetIPAddress -AddressFamily IPv4,IPv6 -ErrorAction SilentlyContinue | Where-Object { $_.AddressState -eq 'Preferred' -and $_.IPAddress -notmatch '^127\.|^::1$|^fe80:' } | ForEach-Object { "$($_.InterfaceAlias) $($_.IPAddress)" }

Show listening ports

List TCP ports waiting for incoming connections and the processes using them.

macOS

lsof -nP -iTCP -sTCP:LISTEN

Linux

ss -lntup

Windows

Get-NetTCPConnection -State Listen

Pretty print

Get-NetTCPConnection -State Listen | ForEach-Object { $p = Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue; [PSCustomObject]@{ Address = $_.LocalAddress; Port = $_.LocalPort; Process = $p.ProcessName; PID = $_.OwningProcess } } | Sort-Object Port | Format-Table -AutoSize

Check whether a local port is in use

Check a specific local port, replacing 3000 with the port you want to inspect.

macOS

lsof -nP -i :<port>

Example

lsof -nP -i :3000

Linux

ss -lntup 'sport = :<port>'

Example

ss -lntup 'sport = :3000'

Windows

Get-NetTCPConnection -LocalPort <port>

Example

Get-NetTCPConnection -LocalPort 3000

Look up a domain's IP address

Check whether DNS can resolve a hostname to an IP address.

macOSLinux

dig <domain>

Example

dig example.com

Windows

Resolve-DnsName <domain>

Example

Resolve-DnsName example.com

Trace the route to a host

Show the network hops toward a destination; missing hops may simply ignore probes.

macOS

traceroute <host>

Example

traceroute example.com

Linux

tracepath <host>

Example

tracepath example.com

Windows

Test-NetConnection <host> -TraceRoute

Example

Test-NetConnection example.com -TraceRoute

Test a remote port

Check whether a remote host accepts TCP connections on a specific port.

macOSLinux

nc -vz -w 3 <host> <port>

Example

nc -vz -w 3 example.com 443

Windows

Test-NetConnection <host> -Port <port>

Example

Test-NetConnection example.com -Port 443

Inspect an HTTP or HTTPS request

Show DNS, connection, TLS and HTTP details to help locate a URL failure.

macOSLinux

curl -v --connect-timeout 5 --max-time 15 <url>

Example

curl -v --connect-timeout 5 --max-time 15 https://example.com/

Windows

curl.exe -v --connect-timeout 5 --max-time 15 <url>

Example

curl.exe -v --connect-timeout 5 --max-time 15 https://example.com/

Network diagnostics

Troubleshoot and inspect system network configurations.

Show network status

List network interfaces and their current status.

macOS

networksetup -listallhardwareports

Linux

ip -brief link

Windows

Get-NetAdapter

Show interface details

Display detailed information for a specific network interface.

macOS

ifconfig <iface>

Example

ifconfig en0

Linux

ip address show dev <iface>

Example

ip address show dev eth0

Windows

Get-NetAdapter -Name <iface>

Example

Get-NetAdapter -Name Ethernet

Set interface state

Enable or disable a network interface.

macOS

sudo ifconfig <iface> down

Example

sudo ifconfig en0 down

Replace down with up to enable the interface.

Linux

sudo ip link set <iface> down

Example

sudo ip link set eth0 down

Replace down with up to enable the interface.

Windows

Disable-NetAdapter -Name <iface>

Example

Disable-NetAdapter -Name Ethernet

Use Enable-NetAdapter to enable the interface.

macOS

sudo wdutil info

Linux

iw dev

Windows

netsh wlan show interfaces

Show configured DNS servers

Display DNS resolver configuration for the system.

macOS

scutil --dns

Linux

resolvectl status

Requires systemd-resolved; inspect /etc/resolv.conf if it is unavailable.

Windows

Get-DnsClientServerAddress

Capture network packets

Capture packets on a network interface; stop the capture with Ctrl+C.

macOSLinux

sudo tcpdump -i <iface>

Example

sudo tcpdump -i en0

Windows

pktmon start --capture

Run pktmon stop to stop the capture. Use pktmon help for additional capture options.

Firewall

Inspect firewall status and manage inbound traffic rules.

Show UFW status

Display the status and rules of the UFW firewall.

Linux

sudo ufw status verbose

List nftables rules

Display the active nftables ruleset.

Linux

sudo nft list ruleset

Show application firewall status

Check whether the macOS application firewall is enabled.

macOS

/usr/libexec/ApplicationFirewall/socketfilterfw --getglobalstate

Show Windows firewall profiles

Display enabled state and default inbound and outbound actions for each profile.

Windows

Get-NetFirewallProfile | Select-Object Name, Enabled, DefaultInboundAction, DefaultOutboundAction

Allow incoming traffic

Add a rule allowing incoming TCP traffic on a specific port.

Linux

sudo iptables -A INPUT -p tcp --dport <port> -j ACCEPT

Example

sudo iptables -A INPUT -p tcp --dport 22 -j ACCEPT

This changes the active iptables rules and may not persist after reboot.

Windows

New-NetFirewallRule -DisplayName "Allow Port <port>" -Direction Inbound -Protocol TCP -LocalPort <port> -Action Allow

Example

New-NetFirewallRule -DisplayName "Allow Port 22" -Direction Inbound -Protocol TCP -LocalPort 22 -Action Allow

Block incoming traffic

Add a rule blocking incoming TCP traffic on a specific port.

Linux

sudo iptables -A INPUT -p tcp --dport <port> -j DROP

Example

sudo iptables -A INPUT -p tcp --dport 80 -j DROP

This changes the active iptables rules and may not persist after reboot.

Windows

New-NetFirewallRule -DisplayName "Block Port <port>" -Direction Inbound -Protocol TCP -LocalPort <port> -Action Block

Example

New-NetFirewallRule -DisplayName "Block Port 80" -Direction Inbound -Protocol TCP -LocalPort 80 -Action Block

Routing

Inspect the routing table and add or remove static routes.

Display routing table

Display the system routing table.

macOSLinux

netstat -rn

Windows

route print

Add static route

Add a route to a destination subnet through a gateway.

macOS

sudo route -n add -net <subnet> <gateway>

Example

sudo route -n add -net {{SUBNET_VAR}} {{GATEWAY_IP_ADDRESS_VAR}}

Linux

sudo ip route add <subnet> via <gateway>

Example

sudo ip route add {{SUBNET_VAR}} via {{GATEWAY_IP_ADDRESS_VAR}}

Windows

New-NetRoute -DestinationPrefix <subnet> -NextHop <gateway> -InterfaceAlias <iface>

Example

New-NetRoute -DestinationPrefix {{SUBNET_VAR}} -NextHop {{GATEWAY_IP_ADDRESS_VAR}} -InterfaceAlias Ethernet

nmap

Network discovery, port scanning and service identification.

Scan network for open port

Find devices on a network with a specific port open.

macOSLinuxWindows

nmap -p <port> --open <subnet>

Example

nmap -p 22 --open {{SUBNET_VAR}}

Discover active devices

Discover active devices on a network without scanning ports.

macOSLinuxWindows

nmap -sn <subnet>

Example

nmap -sn {{SUBNET_VAR}}

Detect service versions

Detect services and versions running on a host.

macOSLinuxWindows

nmap -sV <host>

Example

nmap -sV {{CLIENT_IP_VAR}}

Scan specific ports

Scan specific ports on a host.

macOSLinuxWindows

nmap -p <ports> <host>

Example

nmap -p 22,80,443 {{CLIENT_IP_VAR}}

Scan all TCP ports

Scan all TCP ports on a host.

macOSLinuxWindows

nmap -p- <host>

Example

nmap -p- {{CLIENT_IP_VAR}}

Identify operating system

Attempt to identify the operating system of a host.

macOSLinuxWindows

nmap -O <host>

Example

nmap -O {{CLIENT_IP_VAR}}

Comprehensive host scan

Perform OS detection, version detection, script scanning and traceroute.

macOSLinuxWindows

nmap -A <host>

Example

nmap -A {{CLIENT_IP_VAR}}

Scan for vulnerabilities

Check a host for known vulnerabilities using Nmap scripts.

macOSLinuxWindows

nmap --script vuln <host>

Example

nmap --script vuln {{CLIENT_IP_VAR}}