VTY lines only allowing one session

[smcdonnellc]

We have recently deployed some C1117 routers in our network, the issue is only one user can remote onto the device at one time.

I've checked the vty lines and it matches our other devices (non C1117 routers and switches) which all work fine.

I think the issue might be to do with the vty lines appearing separately in the config (below).  I've tried to delete the vty lines and reconfigure, tried to default them, but you can't remove them.  I've also tried to configure lines 0 - 4 all at once, but it still lists them separately.

line vty 0
session-timeout 10
access-class IT-permitted in
exec-timeout 30 0
authorization exec userAuthorization
login authentication userAuthentication
length 0
transport preferred none
transport input ssh
line vty 1
session-timeout 10
access-class IT-permitted in
exec-timeout 30 0
no activation-character
authorization exec userAuthorization
login authentication userAuthentication
no exec
length 0
transport preferred none
transport input ssh
stopbits 1
line vty 2 4
session-timeout 10
access-class IT-permitted in
exec-timeout 30 0
authorization exec userAuthorization
login authentication userAuthentication
length 0
transport input ssh
line vty 5 14
session-timeout 10
access-class IT-permitted in
exec-timeout 30 0
authorization exec userAuthorization
login authentication userAuthentication
transport input ssh

Anyone have any idea?  Thanks!

Sinead

[Richard Burts · Accepted solution]

There are 2 things that I note in vty 1:

no activation-character I am not sure why this is in the config and suggest that you remove it.

no exec I believe that this is the major part of your problem. This prevents a user establishing a session on this vty. 

I believe that this is what is happening. A user successfully establishes a session on vty 0. Next user attempts to establish a session but is not accepted on vty 1. The only time a user would get to vty 2 is if both vty 0 and 1 are busy. So you are effectively limited to one user. When you correct this on vty 1 then you should have multiple sessions.

[smcdonnellc]

Hi Rick,

Thank you so much for your help, that has sorted the issue!  I can't believe I missed the "no exec" in there.  Really appreciate your help, and also the explanation of why vty 0, 1 and 2-4 are seperate.

Thanks again,

Sinead

[Richard Burts]

Sinead

You are welcome.  I am glad that my suggestions have been helpful. Thank you for marking this question as solved. This will help other participants in the community to identify discussions which have helpful information. This community is an excellent place to ask questions and to learn about networking. I hope to see you continue to be active in the community.

[MHM Cisco World]

For  config you need to NO line vty x then add line vty x-y

If the range includes vty line that have config then it override vty range config 

For the vty busy you need tcp keepalive to down line when idle.

[Richard Burts]

Sinead

In reading through the discussion I noticed this "I think the issue might be to do with the vty lines appearing separately in the config" The reason why they are listed separately is that vty 1 has some parameters that are different from vty 0. When parameters are different they cause separate listing. Note that vty 2 through 4 are all listed together - because they are have the same parameters for their configuration. If you change vty 1 so that it also has the same parameters then all vty will be listed together. (and if vty 1 has the same parameters as vty 0 then your problem about multiple sessions will be fixed)