SSH connection reset by AP9630 before first SSH packet from NMC2

BillP · ‎2021-06-28

Has anyone had problems with an AP9630 sumx firmware 6.8.0 or the latest 6.9.6 and SSH?

I have upgraded it and reset it to factory settings but can't get SSH to work. It looks as if the NMC2 does not even send the first SSH protocol negotiation packet after the TCP setup.

Client: SYN
NMC2: SYN, ACK
Client: ACK
Client: SSH-2.0-PuTTY_Release_0.74
NMC2: ACK
NMC2: RST

The client does not even get a chance to send the Key Exchange Init. Moving the SSH port or disabling SSH stops the TCP negotiation so at least I know the port is open and not firewalled but I don't see anything in logs.

I could understand from looking at previous posts that the NMC2 has had problems with SSH clients with newer protocols but this is the latest firmware from November 2020 and it has yet to start the protocol negotiation.

Any ideas?

BillP · ‎2021-06-28

Hi Andrew,

What's the host name of your NMC? There is a bug that causes behaviour like this if the host name is three of less characters.

i.e. ups.example.local

-Gavan

See Answer In Context

BillP · ‎2021-06-28

Hi Andrew,

What's the host name of your NMC? There is a bug that causes behaviour like this if the host name is three of less characters.

i.e. ups.example.local

-Gavan

BillP · ‎2021-06-28

That was it.

It would be nice to have an FAQ post for this, but at least it will be visible here.

Many thanks.