Hi All,
I'm in the process of setting up a new Virtual Private Server and
am using Plesk to configure to firewall (among other things).
I have the firewall configured how I want it within Plesk.
However, when I SSH into the box and list the firewall rules
(using iptables -L -n) I get way more rules than I setup within
Plesk. I'm thinking that there must be several rules that were
there beforehand as default from the hosting provider. One thing I
do notice, however, is that for a given chain (in this case Input
chain) the very first rule is:
-A INPUT -j VZ_INPUT
The INPUT chain looks something like this (as given by iptables -L -n):
Chain INPUT (policy DROP)
target prot opt source destination
VZ_INPUT all -- 0.0.0.0/0 0.0.0.0/0
ACCEPT tcp -- 190.93.240.0/20 0.0.0.0/0 tcp
dpt:80
ACCEPT tcp -- 108.162.192.0/18 0.0.0.0/0 tcp
dpt:80
blah, blah.....
Chain VZ_INPUT (1 references)
target prot opt source destination
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp
dpt:4643
... all the rest of the rules I entered in Plesk....
VZ_INPUT is a user-defined rule that
Plesk puts in and that chain has all the rules I entered in the
Plesk panel.
My question is: if the above VZ_INPUT rule is the very first rule
in the INPUT chain, does that mean for all input packets jump to
the VZ_INPUT chain and process those rules, thus bypassing all the
other inputs?
The same sort of layout is also present
for the OUTPUT & FORWARD chains.
Any thoughts are appreciated.
Thanks,
Peter