3.5.3. Creating Network Packet Filter Rules
Before assigning any
iptables rules for FTP service, review the information in Section 3.4.1, “Assigning Firewall Marks” concerning multi-port services and techniques for checking the existing network packet filtering rules.
Below are rules which assign the same firewall mark, 21, to FTP traffic. For these rules to work properly, you must also use the VIRTUAL SERVER subsection of Piranha Configuration Tool to configure a virtual server for port 21 with a value of
21 in the Firewall Mark field. See Section 4.6.1, “The VIRTUAL SERVER Subsection” for details.
3.5.3.1. Rules for Active Connections
The rules for active connections tell the kernel to accept and forward connections coming to the internal floating IP address on port 20 — the FTP data port.
The following
iptables command allows the LVS router to accept outgoing connections from the real servers that IPVS does not know about:
/sbin/iptables -t nat -A POSTROUTING -p tcp -s n.n.n.0/24 --sport 20 -j MASQUERADE
In the
iptables command, n.n.n should be replaced with the first three values for the floating IP for the NAT interface's internal network interface defined in the GLOBAL SETTINGS panel of Piranha Configuration Tool.
