Case 1. To check whether port 80 is opened on server1 and monitored by some app there:
1 |
telnet server1 80 |
Case2. If no app listens the port on server, we need to start some monitoring tool first and then try telnet:
Start listening on server:
1 |
ls | nc -l -p 80 |
Try to connect from client:
1 |
telnet server1 80 |