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How does internal routing work with iptables forward?
Hope it’ll help to understand a little bit more how internal routing works with iptables. INPUT, FORWARD, and OUTPUT are separate. A packet will only hit one of the three chains. If the destination is to this server, it hits the INPUT chain. If its source is from this server, it hits OUTPUT.
How to change port number in iptables port forwarding?
#iptables -t nat -A PREROUTING -s 192.168.10.0/24 -p tcp –destination-port 80 Redirect –to-port 10000 As the server on internet listens to port 80 or 443, after altering the port number will it change the packet header to port 10000, if so server will not be able to respond for the port number it receives.
How to accept a packet in iptables firewall?
We first append a rule to the INPUT chain to allow (ACCEPT) traffic from the lo (loopback) interface, then we do the same to allow packets to leave the system through the loopback interface. [root@RHEL5 ~]# iptables -A INPUT -i lo -j ACCEPT [root@RHEL5 ~]# iptables -A OUTPUT -o lo -j ACCEPT
How does iptables allow server to use its own loopback device?
Next, we allow the server to use its own loopback device (this allows the server to access its services running on localhost). We first append a rule to the INPUT chain to allow (ACCEPT) traffic from the lo (loopback) interface, then we do the same to allow packets to leave the system through the loopback interface.
2 Answers. INPUT, FORWARD, and OUTPUT are separate. A packet will only hit one of the three chains. If the destination is to this server, it hits the INPUT chain. If its source is from this server, it hits OUTPUT. If its source and destination are both other machines—it’s being routed through the server—then it hits the FORWARD chain.
Is there a difference between input and forwarding?
No problem here, INPUT only allows dns an http (and some local stuff), forwarding works fine: LAN connects to internet. But my question is: does FORWARD allows all from the outside, or only the ports I configured with INPUT?
What are the forward and NAT rules for Linux?
Here is the chapter about FORWARD and NAT Rules. As it states: For example, if you want to forward incoming HTTP requests to your dedicated Apache HTTP Server at 172.31.0.23, use the following command as the root user: your linux gateway receives a packet from your router.