Iptables is a firewall built into Linux that allows a system administrator to define tables containing chains of rules that determine how network packets should be treated. Packets are processed by sequentially traversing rules in chains within the following tables:
- Raw: This is a default table that filters packets before any other table. It is mainly used for rules related to connection tracking.
- Filter: This is a default table for filtering packets.
- NAT: This is a default table used for network address translation.
- Mangle: This is a default table used for specialized packet alteration and is not used by the Security Group API.
A rule in a chain can cause a jump to another chain, which, in turn, can jump to another chain, and so on. This behavior can be repeated to whatever level of nesting is desired. If the traffic does not match the rules of a...
