# /sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # /sbin/iptables -A FORWARD -i eth0 -o eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT # /sbin/iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT You should now be NATing. You can test this by pinging an external address from one of your internal hosts.

Jan 24, 2011 · iptables tool is used to manage the Linux firewall rules. At a first look, iptables might look complex (or even confusing). But, once you understand the basics of how iptables work and how it is structured, reading and writing iptables firewall rules will be easy. This article is part of an ongoing iptables tutorial series. $> iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to 123.12.23.43 or for dynamic (e.g. a modem - you have to call a number first): $> iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE 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. # /sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # /sbin/iptables -A FORWARD -i eth0 -o eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT # /sbin/iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT You should now be NATing. You can test this by pinging an external address from one of your internal hosts.

iptables -t mangle -A POSTROUTING -o eth3 -d 192.168.5.3 -j MARK --set-mark 0x10503 Using IPMARK target we can replace all the mangle/mark rules with only one: iptables -t mangle -A POSTROUTING -o eth3 -j IPMARK --addr=dst --and-mask=0xffff --or-mask=0x10000

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.

Jan 28, 2020 · Iptables does not keep the rules you created when the system reboots. Whenever you configure iptables in Linux, all the changes you make apply only until the first restart. To save the rules in Debian-based systems, enter: sudo /sbin/iptables–save. To save the rules in Red-Hat based systems, enter: sudo /sbin/service iptables save

iptables -t nat -A POSTROUTING -j MASQUERADE means do the MASQUERADE thing when packets are about to go out (POSTROUTING) – Ricardo Biehl Pasquali Mar 11 '18 at 19:44 @plugwash Sorry. You were right.