Zombie SSH sessions

Was not able to SSH to my switch:

root@ubu:~# ssh -l admin 10.1.1.11 -s netconf

ssh: connect to host 10.1.1.11 port 22: Connection refused

Everything was working the day before and no changes had been made. Did some debugging and found:

DLS1#sh ssh

%No SSHv1 server connections running.

Connection Version Mode Encryption  Hmac         State                 Username

0          2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

0          2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

1          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

1          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

2          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

2          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

3          2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

3          2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

4          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

4          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

5          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

5          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

6          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

6          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

7          2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

7          2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

8          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

8          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

9          2.0     IN   aes128-cbc  hmac-md5     Session started       admin

9          2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

10         2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

10         2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

11         2.0     IN   aes128-cbc  hmac-md5     Session started       admin

11         2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

12         2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

12         2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

13         2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

13         2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

14         2.0     IN   aes128-cbc  hmac-md5     Session started       admin

14         2.0     OUT  aes128-cbc  hmac-md5     Session started       admin

15         2.0     IN   aes256-cbc  hmac-sha1    Session started       admin

15         2.0     OUT  aes256-cbc  hmac-sha1    Session started       admin

DLS1#who

    Line       User       Host(s)              Idle       Location

   2 vty 1     admin      idle                    5d16h 10.113.214.148

   3 vty 2     admin      idle                    6d17h 10.113.214.148

   5 vty 4     admin      idle                    5d00h 10.113.214.148

   6 vty 5     admin      idle                    5d21h 10.113.214.148

   7 vty 6     admin      idle                    5d19h 10.113.214.148

   9 vty 8     admin      idle                    4d22h 10.113.214.148

  10 vty 9     admin      idle                    4d17h 10.113.214.148

  11 vty 10    admin      idle                    3d16h 10.113.214.196

  12 vty 11    admin      idle                    4d00h 10.113.214.148

  13 vty 12    admin      idle                 20:13:53 10.113.214.196

  14 vty 13    admin      idle                 16:44:06 10.113.214.197

  15 vty 14    admin      idle                 18:37:16 10.113.214.148

* 16 vty 15    admin      idle                 00:01:48 10.113.214.196

Reason for the zombie sessions is exec-timeout 0 0 configured under line vty 0 15

Reconfigured exec-timeout and rebooting the switch cleared the hung sessions.