Network address translation (NAT) is a method of remapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device.
#!/bin/bash # first cleanup everything iptables -t filter -F iptables -t filter -X iptables -t nat -F iptables -t nat -X # default drop iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP # allow loopback device iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ACCEPT # allow ssh over eth0 from outside to system About removing the source IP selector/filter to the SNAT rule. An information wasn't provided: if there's also a selector/filter on the outgoing interface, or not. The two rules below would get the same output from iptables -t nat -n -L (but not from iptables -t nat -n -v -L or better iptables-save): Aug 09, 2010 · /usr/local/sbin/iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.18.21/24 --vport 80 -j SNAT --to-source 192.168.17.93 iptables shows - iptables -t nat -L Chain PREROUTING (policy ACCEPT) target prot opt source destination. Chain INPUT (policy ACCEPT) target prot opt source destination. Chain OUTPUT (policy ACCEPT) target prot opt source Like every other iptables command, it applies to the specified table (filter is the default), so NAT rules get listed by iptables -t nat -n -L Please note that it is often used with the -n option, in order to avoid long reverse DNS lookups.
Aug 14, 2015 · Introduction. Iptables is a firewall that plays an essential role in network security for most Linux systems. While many iptables tutorials will teach you how to create firewall rules to secure your server, this one will focus on a different aspect of firewall management: listing and deleting rules.
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT \ --to-destination 10.0.4.2:80 With this command, all HTTP connections to port 80 from the outside of the LAN are routed to the HTTP server on a separate network from the rest of the internal network. linux - iptables: change local source address if $ iptables -t nat -A POSTROUTING --destination 10.0.0.1/32 -j SNAT --to-source 10.0.0.160 2. Using a static route. Alternatively, instead of an iptables rule, add a static route for the destination host to the routing table, using the following syntax: $ ip route add
About removing the source IP selector/filter to the SNAT rule. An information wasn't provided: if there's also a selector/filter on the outgoing interface, or not. The two rules below would get the same output from iptables -t nat -n -L (but not from iptables -t nat -n -v -L or better iptables-save):
May 18, 2016 · 2. POSTROUTING chain – This chain is mainly for SNAT (Source NAT) Note: Read about DNAT and SNAT with the example from here . 3. OUTPUT chain – If the packets get delivered locally, this chain is used. You can view the NAT table using the following command. sudo iptables -t filter --list Mangle table