SystemPrivileged EXEC

show line

Displays line configuration and status information for console, auxiliary, and vty lines, used to verify line settings and monitor user connections.

Syntax·Privileged EXEC
show line

When to Use This Command

  • Check if a vty line is configured for SSH or Telnet access.
  • Verify the number of active sessions and which lines are in use.
  • Troubleshoot login issues by reviewing line timeout and authentication settings.
  • Audit line privilege levels and access-class configurations.

Command Examples

Basic show line output for all lines

show line
   Tty Line Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   Int
     0    0 CTY          -      -    -      -    -    -       0       0     0/0       -
     1    1 AUX   9600/9600    -    -      -    -    -       0       0     0/0       -
   * 2    2 VTY              -      -    -      -    -    -       1       0     0/0       -
     3    3 VTY              -      -    -      -    -    -       0       0     0/0       -
     4    4 VTY              -      -    -      -    -    -       0       0     0/0       -
     5    5 VTY              -      -    -      -    -    -       0       0     0/0       -

Line(s) not in async mode -or- with no hardware support:
1, 2, 3, 4, 5

Tty: line number; Line: line number; Typ: line type (CTY=console, AUX=auxiliary, VTY=virtual terminal); Tx/Rx: transmit/receive speed; A: active (asterisk indicates current session); Modem: modem control; Roty: rotary group; AccO: output access list; AccI: input access list; Uses: number of sessions used; Noise: noise count; Overruns: overrun errors; Int: interface.

Show line with specific line number

show line 2
   Tty Line Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   Int
     2    2 VTY              -      -    -      -    -    -       1       0     0/0       -

Line 2, Location: "", Type: "VT100"
Length: 24 lines, Width: 80 columns
Baud rate (TX/RX) is 9600/9600, no parity, 2 stopbits, 8 databits
Status: Ready, Active, No Exit Banner
Capabilities: none
Modem state: Ready
Special Chars: Escape  Shift  Hold  Stop  Start  Disconnect  Activation
                ^^x    none    no    no    no     none        none
Timeouts:    Idle EXEC    Idle Session   Modem Answer  Session   Dispatch
               00:10:00     never          none            not set
              Session Limit   Dispatch Exit
              not set          not set

Modem type is unknown.
Session limit is not set.
Time until activation is not set.

Shows detailed configuration for line 2 (VTY). Status indicates if line is ready and active. Timeouts show idle EXEC timeout (10 minutes) and idle session (never). Special Chars shows escape sequence (^^x). This helps verify line settings like timeout and authentication.

Understanding the Output

The 'show line' command output displays a table with columns: Tty (line number), Line (line number), Typ (line type: CTY for console, AUX for auxiliary, VTY for virtual terminal), Tx/Rx (transmit/receive speed), A (active flag: '*' indicates the line you are currently using), Modem (modem control status), Roty (rotary group), AccO (outgoing access list), AccI (incoming access list), Uses (number of active sessions), Noise (noise count), Overruns (overrun errors), and Int (associated interface). A line with 'Uses' > 0 indicates active connections. The asterisk in the 'A' column marks your own session. The detailed view for a specific line shows configuration parameters like baud rate, databits, stopbits, parity, status (Ready, Active, etc.), timeout values (Idle EXEC, Idle Session), and special characters. In a real network, you would use this to verify that VTY lines have appropriate timeouts (e.g., exec-timeout 5 0) and that no unauthorized sessions are active. A high 'Noise' or 'Overruns' count may indicate hardware issues. The 'AccO' and 'AccI' columns show if access-lists are applied to restrict access.

CCNA Exam Tips

1.

Remember that an asterisk (*) in the 'A' column indicates the line you are currently using.

2.

Know that 'show line' can be used to verify the number of VTY lines available (default 5) and which are in use.

3.

Be aware that 'show line console 0' shows console-specific details, and 'show line vty 0 4' shows all VTY lines.

4.

The 'Uses' column counts active sessions; a value of 0 means the line is free.

Common Mistakes

Confusing 'show line' with 'show users' — 'show line' shows line configuration, while 'show users' shows active user sessions.

Forgetting that the console line is line 0 (CTY) and auxiliary is line 1 (AUX).

Assuming that a line with 'Uses' 0 is not configured — it may just be idle.

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