Users Guide

Setup and Administration 29
X.509 Certificate Management Prerequisites
Web certificates are necessary to ensure the identity of a remote system and to ensure that information
exchanged with the remote system cannot be viewed or changed by others.
This section explains the administrative prerequisites for ensuring your ability to generate a new X.509
certificate, reuse an existing X.509 certificate, or import a root certificate or certificate chain from
Certification Authority (CA) on each supported operating system.
The X.509 certificate management is provided through the Server Administrator home page for all
supported operating systems.
Firewall Configuration on Systems Running Supported Red Hat
Enterprise Linux Operating Systems
If you enable firewall security when installing Red Hat Enterprise Linux, the SNMP port on all external
network interfaces is closed by default. To enable SNMP management applications such as IT Assistant
to discover and retrieve information from Server Administrator, the SNMP port on at least one external
network interface must be open. If Server Administrator detects that the SNMP port is not open in the
firewall for any external network interface, Server Administrator displays a warning message and logs a
message to the system log.
You can open the SNMP port by disabling the firewall, opening an entire external network interface in
the firewall, or opening the SNMP port for at least one external network interface in the firewall. You can
perform this action before or after Server Administrator is started.
To open the SNMP port using one of the previously described methods, perform the following steps:
1
At the Red Hat Enterprise Linux command prompt, type setup and press <Enter> to start the Text
Mode Setup Utility.
NOTE: This command is available only if you have performed a default installation of the operating system.
The Choose a Tool menu appears.
2 Select Firewall Configuration using the down arrow and press <Enter>.
The
Firewall Configuration screen appears.
3 Select the Security Level by tabbing to it and pressing the spacebar. The selected Security Level is
indicated by an asterisk.
NOTE: Press <F1> for more information about the firewall security levels. The default SNMP port number is 161.
If you are using the X Window System GUI, pressing <F1> may not provide information about firewall security
levels on newer versions of Red Hat Enterprise Linux.
a
To disable the firewall, select No firewall or Disabled and go to step 7.
b To open an entire network interface or the SNMP port, select High, Medium, or Enabled and
continue with step 4.