DA-660-8/16-LX User’s Manual
Managing Communications
4-7
The basic syntax to enable and load an IPTABLES module is as follows:
#lsmod
#modprobe ip_tables
#modprobe iptable_filter
Use lsmod to check if the ip_tables module has already been loaded in the DA-660. Use
modprobe
to insert and enable the module.
Use the following command to load the modules (
iptable_filter, iptable_mangle, iptable_nat
):
#modprobe iptable_filter
NOTE
IPTABLES acts as a packet filter or NAT. Take care when setting up the IPTABLES rules. If the
rules are not correct, remote hosts that connect via a LAN or PPP may be denied access. We
recommend using the Serial Console to set up the IPTABLES.
Click on the following links for more information about IPTABLES.
Observe and erase chain rules,
Define policy rules,
and
Append or delete rules
.
Observe and erase chain rules
Usage:
# iptables [-t tables] [-L] [-n]
-t tables: Table to manipulate (default: ‘filter’); example: nat or filter.
-L [chain]: List List all rules in selected chains. If no chain is selected, all chains are listed.
-n: Numeric output of addresses and ports.
# iptables [-t tables] [-FXZ]
-F: Flush the selected chain (all the chains in the table if none is listed).
-X: Delete the specified user-defined chain.
-Z: Set the packet and byte counters in all chains to zero.
Examples:
# iptables -L -n
In this example, since we do not use the -t parameter, the system uses the default ‘filter’ table.
Three chains are included: INPUT, OUTPUT, and FORWARD. INPUT chains are accepted
automatically, and all connections are accepted without being filtered.
#iptables –F
#iptables –X
#iptables -Z
