add ssh alias configuration

admin-guide/configuration/access/sshd_configuration.md

@@ -41,5 +41,19 @@ files::files:
 
 ```
 
+## Aliases in SSH Certificate
+
+Puppet installs automatically a ssh certificate for the host key.
+See the [user guide](../../../user-guide/ssh_host_key_certificates) on how to configure the corresponding CA on the client side.
+
+If the server is reached using different names/addresses than the hostname, then this aliases can be added to the SSH host key certificate with below Hiera configuration:
+```
+ssh_server::aliases:
+  - 'virtual_host.psi.ch'
+  - 'virtual_host'
+  - '129.129.187.75'
+```
+
+
 ## SFTP Server
 How to enable/disable and configure a sftp server please refer to the [SFTP Server](../files/sftp_server) guide.

user-guide/ssh_host_key_certificates.md

@@ -17,3 +17,5 @@ To accept SSH host keys with a certificate, please update either `~/.ssh/known_h
 @cert-authority * ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBF2xLCCHNmXSeY+qNPmdo/jO2AXrcHyQDqZLBzWVwk2/GqMRDl4mavZLBPyQPNeLGAPc+BHg7iRC65wQQEeYOVU=
 @cert-authority * ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKhIx/obIiiO9AtrUgj7pF8kAgv4g9Dp+DRXilkmlkxK
 ```
+
+This is already configured on Puppet managed RHEL nodes.