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Old 03-04-2019, 10:21 AM
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jdev jdev is offline
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Join Date: Nov 2003
Location: Albuquerque, NM
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Originally Posted by dverbern View Post
"Key exchange failed. No compatible key exchange method. The server supports these methods: diffie-hellman-group16-sha512,diffie-hellman-group14-sha256,diffie-hellman-group-exchange-sha256"
Note the vendor ones are stated in error above are not listed.
This is because you're using a version of VShell that does not implement support for any of the newer key exchange algorithms required by the client.

Support for the diffie-hellman-group-exchange-sha256 key exchange algorithm was first implemented in VShell version 4.1.

You're using VShell version 4.0, so this algorithm is not present in the SSH2 > Key Exchange category of the VShell control panel.

You also made reference to ciphers...
Under "Cipher/MAC", within "MAC", there are a couple of MACs not yet checked such as "SHA2-512" or "SHA2-256". I don't know enough about security to know how these concepts work together.
Ciphers and MACs are components of the key exchange process for SSH2 connections, but the key exchange algorithm itself is at play here, not the Ciphers/MACs.

As I mentioned earlier, the reason why this connection is failing is that the client connecting to VShell is requiring algorithms that your older 4.0 version of VShell did not implement.

If you upgrade your VShell installation to a newer version that supports the diffie-hellman-group-exchange-sha256 key exchange method, this specific client will be able to get past that specific obstacle currently preventing successful connection.
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File Type: png VShell_4.4.1_ControlPanel_SSH2-KeyExchangeCategory.png (42.2 KB, 1565 views)
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