Why i am getting "Paramiko : Error reading SSH protocol banner" in below code? What is the solution for it?

Question

I have function in python,(Assume that i have imported all necessary module),

This function is actually a thread,

 def DL_Iperf(args):
        ssh=paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(server_ip,username="root",password=Password)
some_code

This function is actually a thread and it will be created as many no of UE i have, (Ex: if i have 1 UE than 1 Thread will be created),

So, if i have 1 UE/ 2 UE than its working but if i have 3 UE then it is failing, with error "Paramiko : Error reading SSH protocol banner",

Below is the stderr of the script,

No handlers could be found for logger "paramiko.transport"

Unhandled exception in thread started by <function DL_Iperf at 0x02B8ACF0>
Traceback (most recent call last):

File "C:\Users\qxdm-5\Desktop\Chirag\LTE_11_Perfect_Working\TCP_Latest_2\Windo
ws_UE\slave.py", line 379, in DL_Iperf

ssh.connect(ServerIp,username="root",password=Pwd)

File "build\bdist.win32\egg\paramiko\client.py", line 295, in connect

File "build\bdist.win32\egg\paramiko\transport.py", line 451, in start_client

paramiko.SSHException: Error reading SSH protocol banner

From some reference i found that this is because of some network related issue, but my question is if it network related then why everytime in 3rd call of the function i am getting this error? And how do i resolve it?

Answer 1

I'd guess that the server does not allow (or has problems with opening) three parallel connections from the same client.

Try if you can open three parallel connections using a regular SSH client.

Answer 2

It is not necessarily a network issue. It could be possible that your system may become low in resources after you've created #1 & #2 and then processes the SSH protocol banner slowly (or past the timeout.)

You can adjust the banner_timeout to test this theory.

Search on "banner_timeout" at: http://docs.paramiko.org/en/1.16/api/client.html