To enable host-based authentication with conventional public keys on the client, do the following as
Generate a host key. If SSH Tectia Server has been installed on the same machine, the host key pair
/etc/ssh2/hostkey.pubhas been generated during installation and you can skip this step. Otherwise, give the following command:
# ssh-keygen-g3 -P -H hostkey
Optionally, you can define a custom location or name for the host key in the
ssh-server-config.xmlfile. If SSH Tectia Server is not installed on the client host, you can create the configuration file manually and save it in the
Add the following line in the
<authentication-methods> <authentication-method name="hostbased" /> ... </authentication-methods>
Also other authentication methods can be listed. Place the least interactive method first (this means usually the host-based method).
Do the following as the server administrator:
Copy the client's
/etc/ssh2/hostkey.pubfile over to the server. Note that this requires root permissions on the server, and may require root permissions on the client as well.
SSH Tectia Server looks for the host keys to use for host-based authentication in the
/etc/ssh2/trusted_hostsdirectory on Unix and in the "
C:\Program Files\SSH Communications Security\SSH Tectia\SSH Tectia Server\trusted_hosts" directory on Windows.
You have to name the client's public key as follows on the server:
In the example,
client.example.comis the hostname that the client is sending to the server. When the server receives the client's public key, it forms a path based on the hostname and the key type (
ssh-rsa) and compares the received public key to the key on the disk. If the public key matches and the user's login name in the remote end matches the name the user is trying to log in on the server, the user is let in after the signature check.
To enable host-based authentication on the server, in the
ssh-server-config.xmlfile, under the
authentication-methodselement, add an
<authentication-methods> <authentication action="allow"> <auth-hostbased require-dns-match="no" /> ... </authentication> </authentication-methods>
Also other authentication methods can be allowed.
To force an exact match between the hostname that the client sends to the server and the client's reverse mapped DNS entry, set the
In this case, make sure the
/etc/hostsfile has the fully qualified domain name listed before the short hostname, for example:
18.104.22.168 client.example.com client
Even if you are not using
/etc/hostsas your primary resolver, you may need to add entries to it for the client and the server to allow them to resolve each other's fully qualified domain names (if they are not able to do so otherwise).
Notice that when exact DNS matching is set as required, host-based authentication through NAT (Network Address Translation) will not work.
Using the SSH Tectia Server Configuration tool, host-based authentication can be configured on the Authentication page. See Authentication.
ssh-server-config-toolto take the new configuration in use. See ssh-server-config-tool(8).
Click Apply to take the new settings in use.
To test that host-based authentication works, log in to
ClientUser and run the following command:
$ sshg3 ServerUser@server uptime
You should get back the results of uptime on the server.