Digi TransPort LR54 - Policy Rules

Advanced topics Using the firewall command
Digi TransPort WR Routers User Guide
501
nat
The nat table modifies the source and destination IP addresses and TCP and UDP ports so that
traffic can be sent between private IP networks such as a company network and public IP
networks such as the Internet. The nat table supports these chains: OUTPUT, PREROUTING,
POSTROUTING.
mangle
The mangle table modifies a packet being sent, received, or forwarded by the device. The mangle
table supports these chains: INPUT, OUTPUT, FORWARD, PREROUTING, POSTROUTING.
raw
The raw table marks packets for special treatment. When a packet is received, the raw table is
processed first. The raw table supports these chains: INPUT, OUTPUT, FORWARD, PREROUTING,
POSTROUTING.
Chains
By default, there are multiple chains for directing packets:
INPUT
For packets destined for the device.
OUTPUT
For packets generated by the device.
FORWARD
For packets forwarded by the device.
PREROUTING
For packets before the device has decided to forward the packet, or if the packet has been defined
for the device.
POSTROUTING
For packets that have been forwarded by the device, or if the packet has been generated by the
device.
tlr_port_forward
Used by the nat table. Contains rules associated with port forwarding. Reserved for use by the
TransPort system only. Do not modify these rules.
tlr_wan_input
Used by the filter table. Contains rules associated with WAN configuration. Reserved for use by the
TransPort system only. Do not modify these rules.
tlr_ip_filter_input
Used by the filter table. Contains rules associated with ip-filter for data destined to the device.
Reserved for use by the TransPort system only. Do not modify these rules.
tlr_ip_filter_output
Used by the filter table. Contains rules associated with ip-filter for data originating from the
device. Reserved for use by the TransPort system only. Do not modify these rules.
tlr_ip_filter_forward
Used by the filter table. Contains rules associated with ip-filter for data routing through the device.
Reserved for use by the TransPort system only. Do not modify these rules.
tlr_ip_priority_output
Used by the filter table. Contains rules associated with services on the device that require
outgoing access for correct operation. Reserved for use by the TransPort system only. Do not
modify these rules.
Policy rules
A policy rule defines the default action for a chain; for example ACCEPT or DROP.