Linux : Networking & Security (Day 7)

10 Commands Of Networking You Should Know !!!

Ping

• Explanation: The ping command tests network connectivity by sending ICMP echo requests to a target host and measuring the response time.
• Example: To ping a website (e.g., google.com), open the command prompt (Windows) or terminal (Linux/macOS) and

type: ping google.com        

Traceroute (or tracert in Windows)

• Explanation: Traceroute shows the path taken by packets from your device to a destination, revealing intermediate routers.

Example : Run traceroute google.com in the terminal.        

Netstat

• Explanation: Netstat displays active network connections, routing tables, interface statistics, and more.

Example : Execute netstat -an to see active connections.        

Nmap

• Explanation: Nmap is a powerful network scanner for discovering hosts and services.

Example : Use nmap -p 80,443 google.com to scan common ports on google.com.        

Tcpdump

• Explanation: Tcpdump captures network packets for analysis.

Example : Run sudo tcpdump -i eth0 to capture packets on the eth0 interface.        

Ipconfig (Windows) & Ifconfig (Linux/macOS)

• Explanation: These commands display network interface information.

Example (Windows): ipconfig /all        

Example (Linux/macOS): ifconfig -a        

Dig

• Explanation: Dig retrieves DNS information, including domain records.

Example : dig google.com        

Nslookup

• Explanation: Nslookup also queries DNS records.

Example : nslookup microsoft.com        

Wireshark

• Explanation: Wireshark is a packet analyzer for detailed network traffic inspection.

Example : Open Wireshark, select an interface, and start capturing packets.        

Iperf

• Explanation: Iperf measures network performance (bandwidth, throughput).

Example (server) : iperf -s        

Example (client) : iperf -c server_ip        

Essential Commands Of Security You Should Know !!!

iptables

• Explanation: iptables is a powerful firewall management tool.

Example : To allow incoming SSH traffic, use: $ sudo iptables -A INPUT -p tcp --dport 22 -j ACCEPT        

fail2ban

• Explanation: fail2ban protects against brute-force attacks by banning IP addresses.

Example : Install and configure fail2ban to monitor SSH login attempts.        

ufw (Uncomplicated Firewall)

• Explanation: ufw simplifies firewall management.

Example : To allow HTTP traffic, use: $ sudo ufw allow 80/tcp.        

auditd

• Explanation: auditd provides auditing and monitoring capabilities.

Example : Enable auditing with : $ sudo systemctl start auditd        

semanage

• Explanation: semanage manages SELinux policies.

Example : To allow Apache to write to a directory, use: $ sudo semanage fcontext -a -t 

httpd_sys_rw_content_t '/var/www/html/mydir(/.*)?'