
SSHv1-RSA key returns an error message and generates an event log. The output of the error message is
shown below:
CLI print failure Failure: SSH V1 contains multiple structural vulnerabilities and is no
longer considered secure. Therefore we don't support v1-rsa SSH key any longer, please
generate a new v2-rsa key to replace this old one.
If the system boots from a configuration that contains the
v1-rsa
key, you can expect a boot failure when
logging in through SSH. The workaround is to log in via the Console port, re-generate a new ssh v2-rsa key,
and configure server sshd. It will then be possible to log in via ssh.
The
v2-dsa keyword
is now concealed for the Context Configuration mode
ssh
command
The
v1-rsa
keyword has been removed from the Exec mode
show ssh key
CLI command.
SSH Host Keys
SSH key-based authentication uses two keys, one "public" key that anyone is allowed to see, and another
"private" key that only the owner is allowed to see. You create a key pair, securely store the private key on
the device you want to log in from, and store the public key on the system () that you wish to log into.
SSH host keys are generated within a specified StarOS context. The context is associated with a user interface.
You set or remove an administrative user name having authorized keys for access to the sshd server associated
with context.
Setting SSH Key Size
The Global Configuration mode
ssh key-size
CLI command configures the key size for SSH key generation
for all contexts (RSA host key only).
Step 1
Enter the Global Configuration mode.
[local]
host_name
#
configure
[local]
host_name
(config)#
Step 2
Specify the bit size for SSH keys.
[local]
host_name
(config)#
ssh key-size { 2048 | 3072 | 4096 | 5120 | 6144 | 7168 | 9216 }
The default bit size for SSH keys is 2048 bits.
Configuring SSH Key Generation Wait Time
SSH keys can only be generated after a configurable time interval has expired since the last key generation.
The
ssh key-gen wait-time
command specifies this wait time in seconds. The default interval is 300 seconds
(5 minutes).
Step 1
Enter the context configuration mode.
[local]
host_name
(config)#
context context_name
[local]host_name(config-ctx)#
ASR 5500 System Administration Guide, StarOS Release 21.5
15
Getting Started
SSH Host Keys