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Unable to add a device to NCM

Hi everyone,

I am having trouble adding a Cisco switch c9200L with OS version 17.11.01 to SolarWinds. I am getting the following output:

I have tried logging in to the switch from the SolarWinds poller using the same credentials, and it works fine. So, I don't think the issue is with the credentials.

I have also tried setting the template to "Auto determine" and "Cisco IOS", but neither of those worked. I have another switch of the same model in another site, and I am able to add it to SolarWinds without any problems.

Any ideas what could be causing this?

Thanks.

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Accepted answers

maciej.sandecki

Another possible issue we also faced was change in default supported HMAC algorithms in IOS 17.10+.

In device logs we could see messages like this:

%SSH-3-NO_MATCH: No matching mac found: client hmac-sha2-256,hmac-sha2-512,hmac-sha1,hmac-sha1-96,hmac-md5,none server hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com

We resolved this by configuring supported HMAC ciphers:

ip ssh server algorithm mac hmac-sha2-256 hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-512-etm@openssh.com

All comments

maciej.sandecki

We had a similar issue with different models and found that : (colon) in the banner was causing this issue. I think it was due to incorrect detection of login prompt. Try removing the colon from your banner and see if that helps.

maciej.sandecki

Another possible issue we also faced was change in default supported HMAC algorithms in IOS 17.10+.

In device logs we could see messages like this:

%SSH-3-NO_MATCH: No matching mac found: client hmac-sha2-256,hmac-sha2-512,hmac-sha1,hmac-sha1-96,hmac-md5,none server hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com

We resolved this by configuring supported HMAC ciphers:

ip ssh server algorithm mac hmac-sha2-256 hmac-sha2-256-etm@openssh.com hmac-sha2-512 hmac-sha2-512-etm@openssh.com

yunus.cankat

Indeed, this is exactly the issue I also face after taking a look at the logs :

Connect::start
SetState start: Connecting
SetState end
Connect::BeginConnect
SetState start: ExchangingIdentification
SetState end
ReceiveNotification:start
ReceiveNotification:ExchangingIdentification
ExchangeIdentification:start2
ExchangeIdentification:received SSH-2.0-Cisco-1.25

ExchangeIdentification:sent SSH-1.99-WeOnlyDo.Net

ExchangeIdentification:end
SetState start: Handshaking
SetState end
SendPacket:start
ReceiveNotification:start
ReceiveNotification:Default
ReceiveNotification:EXCEPTION Could not negotiate mac algorithm
CLOSESOCKET14
SetState start: Disconnected
SetState end
MyTimerCallback:start
CLOSESOCKET15

Will applying your command onto the switch itself impact any service as this switch is in production at the moment ?

maciej.sandecki

This should not cause any disruption (it didn't in our case).