UNABLE TO LOGIN: 4 STEP TO CLEAR VTY LINES


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CASE STUDY
—————- 
Unable To Access Switch

—————
SCENARIO
—————
Switch is fine & passing traffic normally, there is no outage in the network.
But, we are not able to access Switch. There is some issue with the VTY lines.

———
ISSUE
———
–> How to get access into the switch ?

–> What needs to be configured on the switch, to avoid VTY lines issue again ?

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SOLUTION
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First Step:

Confirm number of VTY lines
switch# show users
Line User Host(s) Idle Location
0 con 0 idle 05:23:17
130 vty 0 idle 1d03h 144.254.7.118
131 vty 1 idle 1d01h 144.254.7.118
132 vty 2 idle 00:04:36 144.254.8.54


Second Step:

Delete VTY lines
clear vty line < vty line number >
Example: clear vty line 0

If VTY line get hung, clear the TCP connection


Third Step:

Delete TCP connection
Command: clear tcp tcb <Register number>
Here, register number is captured from command, show tcp br
Example:
R1#sh tcp brief
TCB Local Address Foreign Address (state)
6353F5E8 10.10.3.5.1720 10.11.3.24.12871 SYNRCVD
63555A14 10.10.3.5.1720 10.11.3.23.12814 SYNRCVD

clear tcp tcb 6353F5E8


Fourth Step:

Configure session time out for vty lines

Example:
switch(config)# line vty exec‑timeout 6o

Here, 60 represents the 60 minutes.


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