block telnet on a subnet

[MarcW]

I cannot solve how to block telnet on a subnet range.  My assumption is a layer 7 rule, but that's all I got.  How do I block telnet on a MX75? 

[CptnCrnch]

Not a Single Layer 7 rule needed. Just block Access to TCP Port 23 in your regular Policy for this specific subnet 

[MarcW]

Waiting for local admin to run pen test to see if I blocked it correctly and successfully. 

[GIdenJoe]

Actual telnet on devices is run on TCP/23.
So just make an outbound rule that blocks destination port TCP/23 from or to the subnet you want to block it.

Telnetting to other ports is only used to see if you can get a TCP handshake.  But you're not exchanging any commands for that protocol.