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UC-7110 Series User’s Manual Configuring UC-7110
4-7
Append or delete rules:
Usage:
# iptables [-t table] [-AI] [INPUT, OUTPUT, FORWARD] [-io interface] [-p tcp, udp, icmp,
all] [-s IP/network] [--sport ports] [-d IP/network] [--dport ports] –j [ACCEPT. DROP]
-A: Append one or more rules to the end of the selected chain.
-I: Insert one or more rules in the selected chain as the given rule number.
-i: Name of an interface via which a packet is going to be received.
-o: Name of an interface via which a packet is going to be sent.
-p: The protocol of the rule or of the packet to check.
-s: Source address (network name, host name, network IP address, or plain IP
address).
--sport: Source port number.
-d: Destination address.
--dport: Destination port number.
-j: Jump target. Specifies the target of the rules; i.e., how to handle matched packets.
For example, ACCEPT the packet, DROP the packet, or LOG the packet.
Examples:
Example 1: Accept all packets from lo interface.
# iptables –A INPUT –i lo –j ACCEPT
Example 2: Accept TCP packets from 192.168.0.1.
# iptables –A INPUT –i eth0 –p tcp –s 192.168.0.1 –j ACCEPT
Example 3: Accept TCP packets from Class C network 192.168.1.0/24.
# iptables –A INPUT –i eth0 –p tcp –s 192.168.1.0/24 –j ACCEPT
Example 4: Drop TCP packets from 192.168.1.25.
# iptables –A INPUT –i eth0 –p tcp –s 192.168.1.25 –j DROP
Example 5: Drop TCP packets addressed for port 21.
# iptables –A INPUT –i eth0 –p tcp --dport 21 –j DROP
Example 6: Accept TCP packets from 192.168.0.24 to UC-7110’s port 137, 138, 139
# iptables –A INPUT –i eth0 –p tcp –s 192.168.0.24 --dport 137:139 –j ACCEPT
Example 7: Log TCP packets that visit UC-7110’s port 25.
# iptables –A INPUT –i eth0 –p tcp --dport 25 –j LOG
Example 8: Drop all packets from MAC address 01:02:03:04:05:06.
# iptables –A INPUT –i eth0 –p all –m mac –mac-source 01:02:03:04:05:06 –j DROP
NAT
NAT (Network Address Translation) protocol translates IP addresses used on one network into
different IP addresses used on another network. One network is designated the inside network and
the other is the outside network. Typically, UC-7110 connects several devices on a network and
maps local inside network addresses to one or more global outside IP addresses, and un-maps the
global IP addresses on incoming packets back into local IP addresses.
NOTE Click on the following link for more information about iptables and NAT:
http://www.netfilter.org/documentation/HOWTO/NAT-HOWTO.html
NAT Example
The IP address of all packets leaving LAN1 are changed to 192.168.3.127 (you will need to load