How to send packets with PREROUTING in iptables?
Inserting DOCKER -named filter INPUT/FORWARD rules fails because when Docker is restarted they are deleted then inserted (not appended). My best attempt is to insert another PREROUTING chain before Docker’s and send unwanted packets from eth0 (WAN) to a black hole – 0.0.0.1 – because you cannot DROP/REJECT in a nat table anymore.
What does it mean to block a packet in iptables?
Rules can block one type of packet, or forward another type of packet. The outcome, where a packet is sent, is called a target. Targets: A target is a decision of what to do with a packet. Typically, this is to accept it, drop it, or reject it (which sends an error back to the sender). Linux firewall iptables has four default tables.
What are the terminating targets in Linux IPTables?
The terminating targets in Linux iptables are: Accept – this rule accepts the packets to come through the iptables firewall. Drop – the dropped package is not matched against any further chain. When Linux iptables drop an incoming connection to your server, the person trying to connect does not receive an error.
What happens when you drop a package in iptables?
Drop – the dropped package is not matched against any further chain. When Linux iptables drop an incoming connection to your server, the person trying to connect does not receive an error. It appears as if they are trying to connect to a non-existing machine.
How does iptables filter packets based on tables?
Iptables filters packets based on: Tables: Tables are files that join similar actions. A table consists of several chains. Chains: A chain is a string of rules.
What is the forward chain in iptables firewall?
The OUTPUT chain is for any packet leaving the system. And the FORWARD chain is for packets that are forwarded (routed) through the system. The screenshot below shows how to list the filter table and all its rules.