Telnet command shows "connected" for sites forbidden by the rulebase.
3 easy to use methods for open port checker - Open Port
NET Developers' user guide for troubleshooting networking problems Part 2 | Exercises in .NET with Andras Nemes
How do I know if a TCP port is open or closed? - Synology Knowledge Center
How to use telnet to test connectivity to TCP ports | NetBeez
Checking Open Ports (Telnetting, TCPING & Scanners) - IP Mechanic
ubuntu 18.04 - telnet: Unable to connect to remote host: Connection refused when trying to connect running docker image - Stack Overflow
How to verify connectivity using PowerShell
Penetration Testing on Telnet (Port 23) - Hacking Articles
Telnet with Bad Request 400 - Stack Overflow
Using telnet to Test Open Ports - Definition, Importance, Use
How To Perform A Telnet Test
Basic Connectivity Tests – Telnet, PoSH, and curl (great for VCSA appliances!) – VMATT.net
Using telnet to Test Open Ports - Definition, Importance, Use
Ping Specific Port {in Linux & Windows} | phoenixNAP KB
How to ping and test for a specific port from Linux or Unix command line - nixCraft
How to telnet from the Netscaler Access Gateway SNIP to your Citrix STA and verify the firewall port is open - JasonSamuel.com
Using Telnet to test HTTP on port 80 - YouTube
Disabling Telnet Port 23 on Brocade Switches - STORCOM Belgium
How to use telnet to test SSL/https websites – Bearfruit
How to Use Telnet to Test a Specific Port? – Its Linux FOSS
How to use telnet to test connectivity to TCP ports | NetBeez
How to use Telnet (to Check the Status of Ports)
Telnet Disabled Option | FortiGate / FortiOS 6.2.0
Test if a port on a remote system is reachable
