Paramiko : Error reading SSH protocol banner

问题

Recently, I made a code that connect to work station with different usernames (thanks to a private key) based on paramiko.

I never had any issues with it, but today, I have that : SSHException: Error reading SSH protocol banner

This is strange because it happens randomly on any connections. Is there any way to fix it ?

回答1:

It depends on what you mean by "fix". The underlying cause, as pointed out in the comments, are congestion/lack of resources. In that way, it's similar to some HTTP codes. That's the normal cause, it could be that the ssh server is returning the wrong header data.

429 Too Many Requests, tells the client to use rate limiting, or sometimes APIs will return 503 in a similar way, if you exceed your quota. The idea being, to try again later, with a delay.

You can attempt to handle this exception in your code, wait a little while, and try again. You can also edit your transport.py file, to set the banner timeout to something higher. If you have an application where it doesn't matter how quickly the server responds, you could set this to 60 seconds.

回答2:

When changing the timeout value (as TinBane mentioned) in the transport.py file from 15 to higher the issue resolved partially. that is at line #484:

self.banner_timeout = 200 # It was 15

However, to resolve it permanently I added a static line to transport.py to declare the new higher value at the _check_banner(self): function.

Here is specifically the change:

It was like this:


 def _check_banner(self):
        for i in range(100):
            if i == 0:
                timeout = self.banner_timeout
            else:
                timeout = 2

After the permanent change became like this:


 def _check_banner(self):
        for i in range(100):
            if i == 0:
                timeout = self.banner_timeout
                timeout = 200 # <<<< Here is the explicit declaration 
            else:
                timeout = 2

来源：https://stackoverflow.com/questions/25609153/paramiko-error-reading-ssh-protocol-banner

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python

paramiko