Is it possible to disable security codes in ssh gateway?
It is not possible to disable security code that is prompted when you ssh into your Jump server. Doing it would introduce a security hole as it would let users with root access to your Jump server box to simply execute a
su - <username>
and get access to all the servers in the gateway.
We would recommend adding SSH RSA keys so that you don’t have to paste long passwords and instead just have to enter a security code and hence would login with just one step, except that you would be entering the security codes/2FA instead of passwords.
Also, you may want to try out two factor authentications like DUO SECURITY which lets you authenticate with a tap on your mobiles so that you don't have to even worry about typing /pasting any more.