iptasbles rule

lolaferrari
lolaferrari used Ask the Experts™
on
please could you tell me what this rule does

-A INPUT -i ! lo -p tcp -m tcp --dport 123 -m state --state NEW -j DROP
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It is being applied on all interfaces but loopback lo
It works for incoming traffic, TCP port 123.
Any new packet (connection) will be dropped.
So if it is not new connection packet for TCP port 123, it will be dropped.
it will jump to DROP (likely to drop the packet) for incoming traffic which on all but not loop back interface, where the packet is tcp protocol to destination port 123 with state = New
usually port 123 is used for Network Time Protocol

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Commented:
thx
You are most welcome.

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