Re: Query: Stateful parameters Explicitly and Implicitly defined, which is it?

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William Fitzgerald wrote:
Dear experts,

If a rule has a state of NEW does it implicitly imply ESTABLISHED also?

Looking at examples on the web I see references to both.

For example to permit access to an internal Web server, which of the straw-man rules are correct?

Implicit Established Example:
iptables -a FORWARD -i eth0 --dport 80 -m state --state NEW -j ACCEPT

Explicit Established Example:
iptables -a FORWARD -i eth0 --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT

I'm no expert, but i would usually have a rule that accepts any established connections first, followed by ones where the state is new and has the conditions you require. I've also added RELATED below as you'd often want those to be accepted by default as well.

iptables -a FORWARD -m state --state RELATED, ESTABLISHED -j ACCEPT
iptables -a FORWARD -i eth0 --dport 80 -m state --state NEW -j ACCEPT
...

John
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