Files related to networking functionality
The following values may be used:
NETWORKING=answer, where answer is yes or no (Configure networking or not configure networking).
F0RWARD_IPV4=answer, where answer is yes or no (Perform IP forwarding or not perform IP forwarding).
HOSTNAME=/iosfname, where hostname is the hostname of your server.
GATEWAY=gw/p, where gwip is the IP address of the remote network gateway (if available).
GATEWAYDEV=gwdev, where gwdev is the device name (eth#) you use to access the remote gateway.
NOTE: For compatibility with older software, the /etc/HOSTNAME file should contain the same value as HOSTNAME= hostname above. With the new version of Red Hat Linux 6.2 the “FORWARD_IPV4=” parameter is now specified in the “/etc/sysctl.conf file instead of the 7etc/sysconfig/network” file.
The “/etc/sysctl.conf file
In Red Hat Linux 6.2, many kernel options related to networking security such as dropping packets that come in over interfaces they shouldn’t or ignoring ping/broadcasts request, etc can be set in the new “/etc/sysctl.conf file instead of the 7etc/rc.d/rc.local” file. One important consideration is the IPv4 forwarding parameter which is now done via the sysctl program, as opposed to being controlled by the contents of the file in 7etc/sysconfig/network”. The sysctl settings are stored in “/etc/sysctl.conf, and are loaded at each boot before the 7etc/rc.d/rc. local” file is loaded. We’ve already talked about all networking security parameters that we must set into the server in Chapter 3, “Linux General Security”, and for this reason we’ll focus only on the kernel option for IPv4 forwarding.
• To enable IPv4 forwarding on your RH 6.2 system, use the following command: Edit the “/etc/sysctl.conf file and add the following line: