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Cisco Bug: CSCtb01537 - CPPr: Telnet port not closed when transport input none is configured

Last Modified

May 31, 2018

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)


When telnet service is disabled via "transport input none" configured under the
vty lines, the TCP port 23 still shows up in LISTEN state in show control-plane
host open-ports output:

Router#show control-plane host open-ports 
Active internet connections (servers and established)
Prot               Local Address             Foreign Address                 
Service    State
 tcp                        *:22                         *:0              
 tcp                        *:23                         *:0                  
Telnet   LISTEN


This affects all 12.4T IOS releases supporting Control Plane Policing up to
12.4(24)T1. Affects 15.2(4)M1 as well.
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  • Status
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