Direct Routing And Iptables - Red Hat ENTERPRISE LINUX 5 - VIRTUAL SERVER ADMINISTRATION Manual

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However, using the arptables_jf method, VIPs can not be configured to start on boot using

standard Red Hat Enterprise Linux system configuration tools.

To configure each real server to ignore ARP requests for each virtual IP addresses, perform the

following steps:

1. Create the ARP table entries for each virtual IP address on each real server (the real_ip is the IP

the director uses to communicate with the real server; often this is the IP bound to eth0):

arptables -A IN -d <virtual_ip> -j DROP

arptables -A OUT -d <virtual_ip> -j mangle --mangle-ip-s <real_ip>

This will cause the real servers to ignore all ARP requests for the virtual IP addresses, and change

any outgoing ARP responses which might otherwise contain the virtual IP so that they contain the

real IP of the server instead. The only node that should respond to ARP requests for any of the

VIPs is the current active LVS node.

2. Once this has been completed on each real server, save the ARP table entries by typing the

following commands on each real server:

service arptables_jf save

chkconfig --level 2345 arptables_jf on

The chkconfig command will cause the system to reload the arptables configuration on bootup

— before the network is started.

3. Configure the virtual IP address on all real servers using ifconfig to create an IP alias. For

example:

# ifconfig eth0:1 192.168.76.24 netmask 255.255.252.0 broadcast

192.168.79.255 up

Or using the iproute2 utility ip, for example:

# ip addr add 192.168.76.24 dev eth0

As previously noted, the virtual IP addresses can not be configured to start on boot using the Red

Hat system configuration tools. One way to work around this issue is to place these commands in

/etc/rc.d/rc.local.

4. Configure Piranha for Direct Routing. Refer to

Piranha Configuration Tool

3.2.2. Direct Routing and iptables

You may also work around the ARP issue using the direct routing method by creating iptables

firewall rules. To configure direct routing using iptables, you must add rules that create a

Chapter 4, Configuring the LVS Routers with

for more information.

Direct Routing and iptables

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