'Network error: software caused connection abort' when typing into Putty

[martino-cisco]

I'm having a strange problem with one of a number of 2960 switches. When I try to telnet into the switch, i'm able to connect and I get the correct prompt for the login credentials. however as soon as I try typing the login credentials, it gives the error 'Network error: software caused connection abort' and knocks me out.

Additional points:

I've checked 'line vty' commands on config and it is fine.

I don't believe it is the case of adjusting the seconds of keepalives on putty because I've also tried using telnet client from Windows cmd and have the same problem.

Any suggestions please?

[Arunagiri Nallusamy]

Hi Martino,

I assume that the VTY terminal sessions are stuck and have not cleared up. Could you post the output of the following commands?

* show user

* show tcp brief

If in case you see the VTY terminal sessions to be stuck and in IDLE state, could you issue the command clear line vty <vty_no> and attempt a TELNET once again to the box.

Also, could you configure the exec-timeout under the line vty configuration to 5 minutes so that an IDLE user will be disconnected if in case he is inactive for 5 minutes? This could be achieved as follows.

E.g:

line vty 0 5

exec-timeout 5 0

Hope this helps...

Regards,

Arun

[martino-cisco]

Hi Narun,

Thanks for your reply. I don't have access to the switch via console today and will check the outputs you have suggested on Monday and let you know what I find. 

Access via telnet is knocking me straight off once I type the first letter of login credentials.

[Arunagiri Nallusamy]

Hi Martino,

You could reload the box to forcefully kill all the hung telnet sessions and try once again.

[martino-cisco]

Hi Narun,

Nothing unusual from the Telnet sessions. I've also tried restarting it and nothing changes. I did notice that i can't log in with aaa authentication credentials and I have to login with the local default credentials. I am able to ping the aaa server though. Any thoughts?

[lmoody]

I am experiencing the same issue.  Did you ever get a resolution this problem? 

[falodund]

Hello, I just received the same error today.
Issue:

It seems the error was being caused by a configuration error in which i statically assigned the same ip address to separate devices. It is my assumption that upon reaching the login prompt the packets are not arriving at there destination. Which causes putty to disconnect.

Test: If the devices are directly connected to another Cisco device you can run show cdp neighbors detail and you should see the same ip more than once. A less technical option is to reload the device in question and while it is reloading attempt to telnet/ssh to that ip in question. If you are greeted by the login prompt before the problem device is finished rebooting then that confirms that the ip is being used twice within the network

Fix: Change one of the ip address scheme on one of the devices.

[falodund]

Hello, I just received the same error today.
Issue:

It seems the error was being caused by a configuration error in which i statically assigned the same ip address to separate devices. It is my assumption that upon reaching the login prompt the packets are not arriving at there destination. Which causes putty to disconnect.

Test: If the devices are directly connected to another Cisco device you can run show cdp neighbors detail and you should see the same ip more than once. A less technical option is to reload the device in question and while it is reloading attempt to telnet/ssh to that ip in question. If you are greeted by the login prompt before the problem device is finished rebooting then that confirms that the ip is being used twice within the network

Fix: Change one of the ip address scheme on one of the devices.

[amymankar@gmail.com]

I had this problem too, I reboot the device and problem resolved. Thanks for your help !

[falodund]

You're welcome!