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Networking Cheatsheet
Essential networking concepts, protocols, and commands for system administrators and developers.
Network Protocols
HTTP/HTTPSApplication layer protocol for web
TCPTransport layer, reliable connection
UDPTransport layer, connectionless
IPNetwork layer protocol
DNSDomain Name System
Network Commands
ping hostnameTest network connectivity
traceroute hostnameTrace route to host
netstat -tulnShow listening ports
nslookup domainDNS lookup
dig domainDNS information
Network Security
iptables -LList firewall rules
ufw statusCheck firewall status
nmap -sV hostPort scan with version
tcpdump -i eth0Capture network traffic
openssl s_client -connect host:443Test SSL connection
Network Configuration
ifconfigNetwork interface config
ip addrShow IP addresses
route -nShow routing table
hostname -IShow IP address
nmcli device showNetwork manager info
Network Troubleshooting
mtr hostnameNetwork diagnostic tool
telnet host portTest port connectivity
curl -I urlCheck HTTP headers
wiresharkNetwork protocol analyzer
ss -tulnSocket statistics
Network Services
systemctl status nginxCheck web server status
systemctl status sshdCheck SSH service
systemctl status dnsmasqCheck DNS service
systemctl status dhcpdCheck DHCP service
systemctl status iptablesCheck firewall service