Below is an example on how to configure SSH on a Cisco ASA Firewall.
%ASA-3-315004: Fail to establish SSH session because RSA host key retrieval failed.
%ASA-6-315011: SSH session from 192.168.0.10 on interface MGMT for user “Unknown” disconnected by SSH server, reason: “Internal error” (0x00)
conf t
crypto key generate rsa modulus 2048
username ruben password ruben priviledge 15
aaa authentication ssh console LOCAL
ssh stricthostkeycheck
ssh 192.168.0.0 255.255.0.0 MGMT
ssh timeout 15
ssh version 2
ssh key-exchange group dh-group1-sha1
wr mem