C2/B2/A4/A2-Series has SSH session error "nonexistent channel 0" with PuTTY v0.6x

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Article ID: 16099 

Products
C2-Series; firmware 5.02.13.0003, 5.02.14.0002, 5.02.15.0002
B2-Series; firmware 4.02.13.0003, 4.02.14.0002, 4.02.15.0002
A4-Series, firmware 3.03.02.0002
A2-Series, firmware 3.03.02.0002
PuTTY; version 0.61, 0.62

Changes
Attempted to start an SSH session using the PuTTY utility.
Entered username and password credentials.

Symptoms
SSH session does not start.
The system instead responds with an error window:
PuTTY Fatal Error
Disconnected: Received SSH2_MSG_CHANNEL_SUCCESS for nonexistent channel 0

Solution/Workaround
For the C2, upgrade to firmware 5.02.16.0008 or higher.
Release notes state, in the 'Changes and Enhancements in 5.02.16.0008' section:
16423   Resolved an SSH connection issue whereby accessing the switch via PuTTY version 0.6x could terminate the session with an error "Disconnected: Received SSH2_MSG_CHANNEL_SUCCESS for nonexistant channel 0".

For the B2, upgrade to firmware 4.02.16.0008 or higher.
Release notes state, in the 'Changes and Enhancements in 4.02.16.0008' section:
16423   Resolved an SSH connection issue whereby accessing the switch via PuTTY version 0.6x could terminate the session with an error "Disconnected: Received SSH2_MSG_CHANNEL_SUCCESS for nonexistant channel 0".

For the A4, upgrade to firmware 3.03.03.0003 or higher.
Release notes state, in the 'Changes and Enhancements in 3.03.03.0003' section:
16383   Resolved an SSH connection issue whereby accessing the switch via PuTTY version 0.6x could terminate the session with an error "Disconnected: Received SSH2_MSG_CHANNEL_SUCCESS for nonexistant channel 0".

For the A2, upgrade to firmware 3.03.03.0003 or higher.
Release notes state, in the 'Changes and Enhancements in 3.03.03.0003' section:
16383   Resolved an SSH connection issue whereby accessing the switch via PuTTY version 0.6x could terminate the session with an error "Disconnected: Received SSH2_MSG_CHANNEL_SUCCESS for nonexistant channel 0".

Pre-upgrade workaround: Use PuTTY v0.60 instead.

Follow-up: A look-alike issue can occur when running PuTTY v0.63 with the A2-Series. This version's hmac-sha2-256 crypto algorithm is not supported on the A2-Series, and never will be. As seen, please revert to PuTTY v0.61 or v0.62, which use mac-sha1.
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Posted 4 years ago

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