Linux Networking Admin Cheat Sheet

ip -br address

# List interfaces with addresses concisely.

ip route get 1.1.1.1

# Display which route and source address would be used.

sudo ip link set dev eth0 up

# Enable a network interface.

sudo ip addr add 192.168.50.10/24 dev eth0

# Assign an address to an interface.

sudo ip route add 10.20.0.0/16 via 192.168.50.1

# Insert a route into the kernel routing table.

ip neigh show

# Inspect ARP/ND neighbor entries.

dig +trace example.com

# Follow DNS resolution from root to answer.

dig +short MX example.com

# Query mail exchanger records.

curl -v https://example.com

# Show request/response details and TLS handshake summary.

curl -X POST https://api.example.com/items -H 'Content-Type: application/json' -d '{"name":"demo"}'

# Send JSON body in an HTTP POST request.

openssl s_client -connect example.com:443 -servername example.com

# Connect and print TLS handshake details.

ssh -L 5433:127.0.0.1:5432 user@db-bastion

# Forward a local port to a remote host/port through SSH.

ssh-copy-id user@server.example.com

# Copy your public key to a remote account.

sudo tcpdump -i eth0

# Capture packets on a specific interface.

sudo tcpdump -i any host 10.0.0.10 and port 443

# Limit packet capture to a host and service port.

sudo iptables -L -n -v

# Inspect IPv4 firewall rules.

sudo nft list ruleset

# Inspect modern nftables configuration.

sudo ufw status verbose

# Inspect uncomplicated firewall state.

sudo firewall-cmd --list-all

# Inspect zones and allowed services.