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New Member

show sessions is empty after telnet

This is in direct reference to Lab 4.2.4 which we're doing in class:

http://cisco.demo.netacad.net/public/21centuryskills/pdfs/handson_lab.pdf

On step 19, having followed all the instructions and everything right (on Cisco 2600 routers), we type

router>show sessions

no sessions

from the

router#show sessions

no sessions

why is this? Ctrl,SHFT,6 +x showed us sessions, but just telnetting from the router left the show sessions buffer empty? Can anyone explain this please.

Thanks

-cyber

  • Network Management
4 REPLIES
Hall of Fame Super Silver

Re: show sessions is empty after telnet

Cyber

When you telnet to a router it starts an exec session on the router that you telnet to and starts a telnet session on the router that you telnet from. The show sessions command shows how many sessions have been established from the exec session in which it executes. In the lab at step 19 you telnet to the Birmingham router. This starts an exec session on the Birmingham router. When you do show sessions it looks for any telnet sessions that have been started from that exec session (on Birmingham) and there are none. When you do Ctrl, SHFT6 and x it suspends the telnet session and puts you back in your original exec session and show sessions does show that there are active telnet sessions.

I believe the key to understanding this is to focus on which exec session is executing the command. If executed in the exec session on the router that you just telnet to then there will not be active sessions. If executed in the exec session on the original router there will be active sessions.

HTH

Rick

New Member

Re: show sessions is empty after telnet

Thank you rick. I am still trying to work this out logically, so let me see if I get this right:

forgoing the "no hostname" sequence in that lab, and going straight into the telnet portion, this is what we get:

GAD>telnet PHX !

PHX>telnet BHM !

BHM>telnet PHX !

PHX>telnet GAD !

GAD>telnet BHM

BHM>

Now, I should have:

a session on GAD for phoenix and birmingham,

a session on BHM for phoenix

a session on PHX for bitmingham and gadsen

At least, that is what I believe I should have, and according to the lab, it asks for a number of open sessions - not whether you had one or not. These labs are fairly 'directing' with their questions, so you can pretty much assume what "type" of answer they are looking for. From what I see, I should be able to issue the following command:

BHM>show sessions

!!and I should get a screen similar to the following:

Conn Host Address Byte Idle Conn Name

* 1 172.16.1.10 172.16.1.10 0 0 172.16.1.10

2 172.16.1.11 172.16.1.11 0 12 PHX

but you are saying that it is only going to show what sessions were suspended before I left birmingham the first time? So I can't telnet in, out, then back in, out and back in again and expect to see any sessions? Sorry if I sound confused - but I am! LOL

-cyber

Hall of Fame Super Silver

Re: show sessions is empty after telnet

Cyber

Having taught Cisco classes for a good amount of time I am aware of their tendency to make labs pretty directing and having looked through the instructions for this lab I agree that it does kind of direct you toward answers. I believe that there are several objectives that they want to achieve in this lab and they include emphasizing that you can telnet to a router, from that router you can telnet to another router, can suspend that telnet session, can telnet to another router (stringing a series of telnet sessions together); that you can have multiple telnet sessions from a single router (and from a single exec session) to multiple destinations; that you can suspend one telnet session and can resume another telnet session.

I also believe that they want to help you understand the concept of an exec session and of a telnet session. You start an exec session when you log into a router. When you successfully telnet to another router it starts an exec session on that router. If you suspend the telnet session, then you return to the original exec session. When you do show session you exhibit the sessions started from that exec session.

As I understand your summary, there will be two exec sessions on BHM (the first session created when you telnet from PHX to BHM and the second when you telnet from GAD to BHM). The first exec session will show a session (because you telnetted from BHM to PHX) and the second exec session will not show any sessions. The point is to understand the concept of multiple exec sessions existing on the router at the same time.

It might be interesting to compare the results of show user (which shows all sessions on a particular router) with the result of show session (which shows any sessions created from a particular exec session).

HTH

Rick

New Member

Re: show sessions is empty after telnet

Thank you again rick. I will try this lab again on friday in the class (where I can chain the 3 routers together) and see what the results of that are. But, I see now what you mean. So, again, thank you. I will leave this message as not totally answered until I can come back in and post the results on friday of redoing the lab with the show users option.

That really helped a lot! I appreciate it!

-cyber

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