We specify that we want to apply Destination NAT (DNAT) to the selected packets (-j DNAT) and of course the target IP and port with --to-destination 10.0.0.1:80. If you only care about the port because the public server has multiple IPs and you want the rule to work for all of them simply omit -d 32.0.0.1 .
Destination NAT (DNAT) rewrites the destination address, which is the firewall address, to the real server addresses, then iptables forwards incoming traffic to these servers. Someday, when IPv6 is widely implemented, we can say good-bye to NAT, except for those times when we really want it. Aug 29, 2017 · DNAT: This is a virtual state used to represent packets whose destination address was changed by rules in the nat table. SNAT: Like DNAT, this state represents packets whose source address was changed. Thus, you need to place a rule like the one below, usually at the very top. (If this isn’t the first rule, use -I to place it at the top.) Enable masquerade on eth1 to rewrite the source address on outgoing packets. If you truly want symmetric NAT, you'll need the --random at the end: iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE --random Configure forwarding rules. By default, iptables will forward all traffic unconditionally. *nat # ここにnat関係の記述 COMMIT 【Ex1】IPマスカレードの指定 [root@centos6 ~]# iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -j MASQUERADE ip nat pool natpool1 xx.yy.124.161 xx.yy.124.161 netmask 255.255.255.252. ip nat inside source list corenat1 pool natpool1. This was intended to identify the traffic to nat (access-list corenat1), then create a nat pool with one address in it, and finally NAT the identified traffic to the new address.
Apr 11, 2020 · Notice that these are iptables commands minus the iptable command. Feel free to edit this to file and save when complete. Then to test simply: sudo iptables-restore < /etc/iptables.rules. NOTE: With iptables 1.4.1.1-1 and above, a script allow you to test your new rules without risking to brick your remote server.
*nat # ここにnat関係の記述 COMMIT 【Ex1】IPマスカレードの指定 [root@centos6 ~]# iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -j MASQUERADE
#iptables -t nat -A POSTROUTING -s 172.16.6.2 -j SNAT --to-source 1.1.1.1 DNAT 如果是一个 DNAT 的过程的话，写规则时的链就不同，应该写在PREROUTING链中：
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 POSTROUTING -s 192.168.1.0/24 -o eth1 \ -j SNAT --to 1.2.3.0/24 The same logic applies to addresses used by the NAT box itself: this is how masquerading works (by sharing the interface address between masqueraded packets and `real' packets coming from the box itself). This tutorial shows how to set up network-address-translation (NAT) on a Linux system with iptables rules so that the system can act as a gateway and provide internet access to multiple hosts on a local network using a single public IP address. #iptables -t nat -A POSTROUTING -s 172.16.6.2 -j SNAT --to-source 1.1.1.1 DNAT 如果是一个 DNAT 的过程的话，写规则时的链就不同，应该写在PREROUTING链中： The network address translation table (or "nat") that is made available to iptables is merely a "configuration database" for NAT mappings only, and not intended for filtering of any kind. iptable_filter module Registers the filter table, used for general-purpose filtering (firewalling). security_filter module Destination NAT (DNAT) rewrites the destination address, which is the firewall address, to the real server addresses, then iptables forwards incoming traffic to these servers. Someday, when IPv6 is widely implemented, we can say good-bye to NAT, except for those times when we really want it.