When use telnet/ssh then switch stop responding even ping does not work

[olly ahmed]

Hi,

I am having a problem which is normally ping works to a switch. I also gets the switch as cdp neighbor from a connected switch as well as can ping the switch from that connected switch. I try to telnet / ssh from connected witch it says connection denied "% Connection refused by remote host" but it still respond to icmp / ping. But when I telnet / ssh from a specific host the switch even stops responding to ping even from directly connected switch. Can anyone specify the cause ?

[Richard Burts]

I am not sure why it would behave differently when you attempt telnet/ssh from the connected switch than from a specific host. The logical explanation might be that the problem switch is configured with access-class for its vty ports which do not permit the switch but do permit the specific host.

I experienced similar symptoms with a switch in a customer network which turned out to be a memory leak in the version of code that the switch was running. You might check on the problem switch to see if it is experiencing low memory issues.

HTH

Rick

[olly ahmed]

Hi Rechard,

Thanks for your reply. Please be informed that I got more than 5/6 switches are behaving same.I guess there is no memory issue as it is not happening for only one switch.

[Raja_D]

Hi Olly, 

Please share line vty configuration done on both switches(from which you are trying and that switch to which you want to connect). I am suspecting that the transport input & output configuration might not be set properly.  

[olly ahmed]

Hi James,

Please be informed that there is no configuration issue at the switch from which I am trying to telenet. The swich stop even responding to ping when try to telnet from a windows server. And as I mentioned I can not telenet / ssh to the intended switch.

[Raja_D]

Is there any acl configured on line vty if so permit the windows server ip in that acl and then try to telnet to that switch. Also I hope so,  that you have the set the enable command using enable secret xxx on the switch end. 

[olly ahmed]

Hi James,

I think you could not get my question. If ACL is blocking the ip of windows server then it will simply deny telnet / ssh from that server but still switch will respond to ping request. But the issue is after trying telnet / ssh switch even stop reaponding to ping request. And after 5/10 minutes it start responding again.

[olly ahmed]

Can anyone help ?