Which option must be used with ifconfig, to also see interfaces that are down?

What is the command to add another IP address to an interface that already has (at least)
one IP address?

The command route shows the following output: Which of the following statements is
correct?

A network client has an ethernet interface configured with an IP address in the subnet
192.168.0.0/24. This subnet has a router, with the IP address 192.168.0.1, that connects
this subnet to the Internet. What needs to be done on the client to enable it to use the router
as its default gateway?

A server with 2 network interfaces, eth0 and eth1, should act as a router. eth0 has the IP
address 192.168.0.1 in the subnet 192.168.0.1/24 and eth1 has the IP address 10.0.0.1 in
the subnet 10.0.0.0/16. The routing table looks fine, but no data is traversing the networks.
Which TWO of the following need to be done?

What command is used to add a route to the 192.168.4.0/24 network via 192.168.0.2?

Which of the following sentences is true, when using the following /etc/pam.d/login file?

#%PAM-l.0 auth required /lib/security/pam_securetty.so auth required
/lib/security/pam_nologin.so auth sufficient /lib/security/pam_unix.so shadow nullok md5
use_authtok auth required /lib/security/pam_ldap.so use_first_pass account sufficient
/lib/security/pam_unix.so account required /lib/security/pam_ldap.so password required
/lib/security/pam_cracklib.so password sufficient /lib/security/pam_unix.so nullok
use_authtok md5 shadow password required /lib/security/pam_ldap.so use_first_pass
session optional /lib/security/pam_console.so session sufficient /lib/security/pam_unix.so
session required /lib/security/pam_ldap.so

LDAP-based authentication against a newly-installed LDAP server does not work as
expected. The file /etc/pam.d/login includes the following configuration parameters. Which
of them is NOT correct?

What is the advantage of using SASL authentication with OpenLDAP?

In a PAM configuration file, which of the following is true about the required control flag?