Connection fails to Cisco Small Business switch #15

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opened 2026-04-21 13:59:34 +02:00 by tux · 5 comments

tux commented

2026-04-21 13:59:34 +02:00

Owner

When attempting to connect to Cisco Small Business devices with their specific OS variant, the SSH connection fails, in the log with:

Password auth result session_id=6656c85f-688a-4335-a0ae-2e3dcd9053e4 success=false

When checking on the device on a working session (e.g. from putty) at the time of the connection attempt there is:

%SSHD-I-LOG: SSH log: WARNING: no suitable primes in /etc/ssh/moduli

The option to enable legacy algorithms is enabled already.

When attempting to connect to Cisco Small Business devices with their specific OS variant, the SSH connection fails, in the log with: `Password auth result session_id=6656c85f-688a-4335-a0ae-2e3dcd9053e4 success=false` When checking on the device on a working session (e.g. from putty) at the time of the connection attempt there is: `%SSHD-I-LOG: SSH log: WARNING: no suitable primes in /etc/ssh/moduli` The option to enable legacy algorithms is enabled already.

tux commented

2026-04-21 20:52:30 +02:00

Author

Owner

Fixed in #f0505525f9

Fixed in #f0505525f9476ed6bc41cd4f8386737d3ec01ee2

tux commented

2026-04-21 22:05:36 +02:00

Author

Owner

Resolved in release 0.10.1

Resolved in release [0.10.1](https://git.fiedler.live/tux/shellstation/releases/tag/v0.10.0)

tux closed this issue

2026-04-21 22:05:36 +02:00

tux commented

2026-04-22 08:35:22 +02:00

Author

Owner

There is still an issue with these variant of devices.

Some more information, the problem is with the Cisco models "SG350-10 10-Port Gigabit Managed Switch" (Firmware Version: 2.5.8.15) and also "Catalyst 1300 Series Managed Switch" (Firmware Version: 4.1.7.17).

There is no special configuration on these devices regarding SSH, the only relevant parts in the config:

line ssh
 login authentication SSH
 enable authentication SSH
ip ssh server

The error with the moduli primes no longer appears, but the connection still fails with "Channel send error".

Append some log files:

SG350_issue.log: When the connection fails on shellstation for this type of device
SG350_OK.log: A successful connection to the device from a Linux server
C1300_issue.log: When the connection fails on shellstation for this type of device
C1300_OK.log: A successful connection to the device from a Linux server

There is still an issue with these variant of devices. Some more information, the problem is with the Cisco models "SG350-10 10-Port Gigabit Managed Switch" (Firmware Version: 2.5.8.15) and also "Catalyst 1300 Series Managed Switch" (Firmware Version: 4.1.7.17). There is no special configuration on these devices regarding SSH, the only relevant parts in the config: ``` line ssh login authentication SSH enable authentication SSH ip ssh server ``` The error with the moduli primes no longer appears, but the connection still fails with "Channel send error". Append some log files: - SG350_issue.log: When the connection fails on shellstation for this type of device - SG350_OK.log: A successful connection to the device from a Linux server - C1300_issue.log: When the connection fails on shellstation for this type of device - C1300_OK.log: A successful connection to the device from a Linux server

SG350_issue.log

6.4 KiB

SG350_OK.log

11 KiB

C1300_OK.log

11 KiB

C1300_issue.log

6.3 KiB

tux reopened this issue

2026-04-22 08:35:22 +02:00

tux commented

2026-04-22 09:12:43 +02:00