Linux commands

This page describe linux commands, to learn and don’t forget it.

1. Conecction commands

1.1. nslookup url

Show the IP address of a domain name.

Example:

nslookup google.com

Response:

Server:         xxx.xxx.xxx.xxx
Address:        xxx.xxx.xxx.xxx

Non-authoritative answer:
Name:   google.com
Address: xxx.xxx.xxx.xxx

1.2. openssl

1.2.1. Show digital certifcate of a server

openssl s_client -connect ipAddress:port