Re: sshd fatal - no matching cipher found

On Wed, Feb 19, 2020 at 3:33 PM Patrik Schindler <poc@xxxxxxxxxx> wrote:

Hello Jack,

Am 19.02.2020 um 19:09 schrieb Jack Woehr <jwoehr@xxxxxxxxxxxxxxxxxxxxxxxx

:

Unfortunately, I don't know how to suppress this message in IBM i.

The way to "suppress" it is to have a competent network security group

analyze your exposure and mitigate that.

Ssh is an encrypted protocol. I don't know of any firewall solution which
can look into an encrypted ssh session to see what it's up to. What kind of
magic do you expect the competent network security group to do? :-)

but the firewall would be able to block based on the IP address of the SSH
traffic, no ?

My suggestion would be to not expose IBM i to the internet at all. And if

that's really necessary *and* ssh (aka Sftp) must be reached from outside
for one reason or another, it can be that Sftp-Peers utilize dynamic
addresses, so it's not possible to predict where legit connections come
from. Yes, it would be possible to exclude "bad" country's IP allocations.
Been there, done that. I'd never open that particular Box of Pandora again.

blocking SSH means terminal access to PASE is blocked over the web?

what I do not understand is, if SSH only works using public/private key
pairs, what is the risk of having your SSH port open to internet access?
Just another layer of security? Block denial of service attacks?

-Steve