With that, a simple iptables -L POSTROUTING -t mangle -v gives you a perfect counter for each flow. And as mentioned before it does also account the traffic of RELATED connections in the category of the parent connection.

The rule uses the NAT packet matching table (-t nat) and specifies the built-in POSTROUTING chain for NAT (-A POSTROUTING) on the firewall's external networking device (-o eth0). POSTROUTING allows packets to be altered as they are leaving the firewall's external device. sudo iptables -t nat -A POSTROUTING -d 239.0.2.4 -o wlan0 -j DNAT --to 192.168.1.3 My problem is that a relay of my rtsp local server accepts only a multicast ip-address but I would that the packets are sent with a classical ip-address. Thanks to something different. This is done in the POSTROUTING chain, just before it is finally sent out; this is an important detail, since it means that anything else on the Linux box itself (routing, packet filtering) will see the packet unchanged. It also means that the `-o' I'm specially in doubt of PREROUTING and POSTROUTING. As far as a I know: - DNAT can be made with PREROUTING - SNAT can be made with POSTROUTING NAT makes DNAT to change the target of a packet, and makes SNAT to change the source of a packet, so I conclude: - PREROUTING is for incoming traffic - POSTROUTING is for outcoming traffic Is it correct? PREROUTING is one side, and POSTROUTING is the other side. – Ipor Sircer Nov 13 '16 at 5:21 Ok I thought that after PREROUTING, the outcome was automatically handled :) – Duke Nukem Nov 13 '16 at 13:08 firewall-cmd --permanent --direct --add-rule ipv4 nat POSTROUTING 0 -p tcp -s 192.168.15.105/32 -j SNAT --to-source 192.168.25.121. gives a "success". I do a firewall-cmd --reload afterwards. But if I try to examine the table with iptables -t nat -nvL POSTROUTING the rule is not listed. iptables is a command line interface used to set up and maintain tables for the Netfilter firewall for IPv4, included in the Linux kernel. The firewall matches packets with rules defined in these tables and then takes the specified action on a possible match.

Sep 17, 2018 · sudo iptables -t nat -A POSTROUTING -o enp0s9 -p udp --dport 123 -j MASQUERADE OR sudo iptables -t nat -A POSTROUTING -o enp0s9 -p udp --dport 123 -j SNAT --to-source 192.168.2.125 NOTE: One mistake that is easy to make in this step is assuming the you specified is the one actually used for the outbound communication. Use “route -n

Feb 18, 2020 · Related: Linux Iptables Delete postrouting Rule Command. Conclusion. We explained to you how to list and remove/delete iptables pretrouting chain nat rules on your Linux based system. The -D or --delete option delete one or more rules from the selected chain. There are two versions of this command, the rule can be specified as a number in the iptables: Small manual and tutorial with some examples and tips Written by Guillermo Garron Date: 2012-04-18 14:06:00 00:00. This is a small manual of iptables, I'll show some basic commands, you may need to know to keep your computer secure.

iptables --table nat --append POSTROUTING --out-interface bond0 -j MASQUERADE iptables --append FORWARD --in-interface eth1 -j ACCEPT server iptables --table nat --append POSTROUTING --out-interface eth0 -j MASQUERADE iptables --append FORWARD --in-interface bond0 -j ACCEPT Iptables NAT FW (Without Full NAT, Just Insert)

Dec 07, 2013 · A Postrouting chain in NAT table means altering the IP packet after the routing is completed. Logically, a postrouting can be used to change the Source Address. As the routing is completed and destination has his own address, the only unknown address that can be masked is the Source. This is why postrouting is used for SNAT. The rule uses the NAT packet matching table (-t nat) and specifies the built-in POSTROUTING chain for NAT (-A POSTROUTING) on the firewall's external networking device (-o eth0). POSTROUTING allows packets to be altered as they are leaving the firewall's external device. sudo iptables -t nat -A POSTROUTING -d 239.0.2.4 -o wlan0 -j DNAT --to 192.168.1.3 My problem is that a relay of my rtsp local server accepts only a multicast ip-address but I would that the packets are sent with a classical ip-address. Thanks to something different. This is done in the POSTROUTING chain, just before it is finally sent out; this is an important detail, since it means that anything else on the Linux box itself (routing, packet filtering) will see the packet unchanged. It also means that the `-o'