Hi Ahmedo,

The best way is to use an ACL to deny all port 23 traffic. Page 210 https://dell.to/35yvWoE Let me know if you have any additional questions.

I know telnet is using the TCP any way, I did create the rule for blocking udp, and the port still open what to do???

access-list DenyPort23 deny udp any eq 23 any eq 23

@DELL-Josh Cr 

I did run the following command but it does not block the port 23

SwitchName(config)#access-list DenyPort23 deny tcp any eq 23 any eq 23

Please help!

@DELL-Josh Cr 

Try blocking UDP as well.

using powershell to check if the port is open or close

Test-NetConnection IPAddress -Port 23

How are you testing it? Are you opening a telnet session or just scanning the port?

yesssssss correct! that solved the issue,

thanks for all your help @DELL-Josh Cr 

It is probably the implicit deny all at the end the acl. So you need to add a permit all for other traffic. SwitchName(config)#access-list DenyPort23 permit every any any

Did you do (config)#ip access-group DenyPort23

To apply it to all interfaces?

Every time I ran this command I lose the connection with the switch! And I have to reboot the switch (Start from Startup-Config again) to get connected to it.

@DELL-Josh Cr