Correct Answer: To configure the verification mode of the host account to use LDAP for authentication, you need to set up the system to use an LDAP server for user account verification. Assuming you are using a Red Hat-based system, you can follow these steps to achieve the required configuration. First, ensure you have the necessary packages installed to support LDAP authentication. You can install the required packages using the following command:
1. Open a terminal and use the `yum` package manager to install the necessary packages:
```
sudo yum groupinstall 'directory-client'
```
This command will install `krb5-workstation`, `pam-krb5`, and `sssd` among others which are required for LDAP authentication.
2. After installing these packages, open the Authentication Configuration tool using the command:
```
sudo system-config-authentication
```
3. In the Authentication Configuration tool, go through the following steps:
- Set the User Account Database to LDAP.
- Set the LDAP Search Base DN to `dc=example,dc=com`.
- Set the LDAP Server to `ldap://instructor.example.com`. Note that you should enter the domain name and not the IP address.
- Download the CA certificate from `http://ip/dir/ldap.crt` and specify its path in the configuration.
- Set the Authentication Method to LDAP password.
- Apply the changes.
4. Verify that the configuration is working by checking if the user `ldapuser40` is recognized by the system using the command:
```
getent passwd ldapuser40
```
If the command returns information about the user, then the LDAP configuration is successful, and the user should be able to log in using the specified password 'password'. Note that the user's home directory will not be available unless autofs is configured separately, as mentioned.