Network Management

Blue Coat Invalid data received from remote server in NCM

When you attempt to add the BlueCoat node in NCM you receive Test Failed Connection refused. Invalid data received from remote server. Protocol error.

First published date

11/8/2018 9:53 AM

Last published date

11/8/2018 9:53 AM

Overview

When you attempt to add a Blue Coat node in NCM you receive Test Failed Connection refused.

Product section

Network Configuration Manager

Cause

SSH2

NCM tries to negotiate an AES algorithm first (any type). If that fails, NCM tries TripleDES. If TripleDES is not available, NCM tries Blowfish. If Blowfish fails, NCM drops the connection instead of trying DES, which most (new) servers don't support because of its poor security.

For more Details please see the KB post below.

NCM supported encryption protocols for SSH

If the device has CSCipher = aes128-cbc, when NCM sees the Cipher it tries to get the connection using AES. The device refuses the connection because the device is not configured to use this AES cipher and the connection is refused.

Resolution

This is known issue. SolarWinds suggests trying the following workarounds:

Configure device and deny usage of any other ciphers except AES-256 on device side.
Use the SSH Auto
Enable Telnet and download the device configuration

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