[Linux] Verifying Network Connection

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Verifying Network Connection

• Telnet
• Netstat

Telnet

apt-get update -y && apt-get install telnet
#telnet {ip} {port}
telnet naver.com 80

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Netstat

• -a: Shows all current active TCP connections and the ports on which the computer is listening.
• -r: Displays the routing table for your computer. This is the same as using the route print command.
• -n: Display active network connections and their status without resolving hostnames or port names.
• -t: shows tcp protocol
• -u: shows udp protocol
• -p: Display all active connections for the specified protocol. The protocols can be TC, UDP, ICMP, and IP.

apt-get update -y && apt-get install net-tools

# see whether port is in use
netstat -an | grep {port}

# shows port and program listening to TCP
netstat -nlpt

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