Linux

hello everyone,

tomorrow I'll install linux on my pc and I collected a few commands and configurations to experiment with.

I know the they mean but the consequences I have to test

If someone knows more about the commands, give some explanation, thanks

max-lease-time 86400;
default-lease-time 86400;
Option domain-name-servers 193.190.59.97, 193.190.59.100, 193.190.56.250;
subnet 192.168.0.0 netmask 255.255.255.0
{range 192.168.0.1 192.168.0.99;
option routers 192.168.0.100;}
subnet 192.168.1.0 netmask 255.255.255.0
{range 192.168.1.1 192.168.1.99;
option routers 192.168.1.100;}
subnet 10.1.0.0 netmask 255.255.0.0
{nonauthoratative}
ddns-update-style ad-hoc;

iptables -F
iptables -t nat -F
iptables - -delete-chain
iptables - -table nat - -delete-chain

iptables –t nat –A POSTROUTING –o eth0 –j MASQUERADE

#!/bin/bash
iptables --table filter --flush
iptables --table filter --delete-chain
iptables --table filter --zero
iptables --table nat --flush
iptables --table nat --delete-chain
iptables --table nat --zero
iptables --table mangle --flush
iptables --table mangle --delete-chain
iptables --table mangle --zero
iptables --table filter --policy INPUT ACCEPT
iptables --table filter --policy OUTPUT ACCEPT
iptables --table filter --policy FORWARD ACCEPT
iptables --table nat --policy PREROUTING ACCEPT
iptables --table nat --policy POSTROUTING ACCEPT
iptables --table nat --policy OUTPUT ACCEPT
iptables --table mangle --policy INPUT ACCEPT
iptables --table nat --policy OUTPUT ACCEPT
iptables --table nat --policy FORWARD ACCEPT
iptables --table nat --policy POSTROUTING ACCEPT
echo “Hallo $USER”
echo “de iptables zijn gereset naar hun standaard waarden”

chmod +x /etc/cleantables sh cleantables

iptables –L –n

#!bin/bash
iptables - -table filter - -policy INPUT DROP
iptables - -table filter - -policy OUTPUT DROP
iptables - -table filter - -policy FORWARD DROP
iptables –t filter –A INPUT –s 127.0.0.1 –i lo –j ACCEPT
iptables –t filter –A OUTPUT –d 127.0.01 –o lo j ACCEPT
echo “de chains in de filter table staan op drop”
echo “verkeer van en naar localhost is toegestaan”

iptables - -table filter –A INPUT –s 192.168.0.0/24 –d 192.168.0.100 –i eth1 –j ACCEPT
iptables - -table filter –A OUTPUT –s 192.168.0.100 –d 192.168.0.0/24 –o eth1 –j ACCEPT

iptables –table filter –A INPUT –s 192.168.1.0/24 –d 192.168.1.100 –i eth2 –j ACCEPT
iptables –table filter –A OUTPUT –s 192.168.1.100 –d 192.168.1.0/24 –o eth2 –j ACCEPT

iptables –table filter –A FORWARD –s 192.168.0.0/24 –d 192.168.1.0/24 –i eth1 –j ACCEPT
iptables –table filter –A FORWARD –s 192.168.1.0/24 –d 192.168.0.0/24 –i eth2 –j ACCEPT

iptables –t filter –A FORWARD –i eth1 –p tcp - -tcp-flags SYN,ACK,RST,FIN SYN –j ACCEPT
iptables –t filter –A FORWARD –i eth0 –p tcp - -tcp-flags SYN,ACK,RST,FIN SYN,ACK –j ACCEPT
iptables –t filter –A FORWARD –p tcp - -tcp-flags SYN,ACK,RST,FIN ACK –j ACCEPT
iptables –t filter –A FORWARD –p tcp - -tcp-flags SYN,ACK,RST,FIN ACK,FIN –j ACCEPT
iptables –t filter –A FORWARD –p tcp - -tcp-flags SYN,ACK,RST,FIN RST –j ACCEPT

iptables –A FORWARD –p tcp –m state - -state ESTABLISHED –j ACCEPT
iptables –A FORWARD –p tcp –m state - -state NEW –i ! eth0 –j ACCEPT

iptables –A FORWARD –p udp –m state - -state ESTABLISHED –j ACCEPT
iptables –A FORWARD –p udp –m state - -state NEW –i ! eth0 –j ACCEPT

iptables - -table filter –A OUTPUT –o eth0 –p icmp - -icmp-type echo-request –j ACCEPT
iptables - -table filter –A INPUT –i eth0 –p icmp - -icmp-type echo-reply –j ACCEPT

iptables - -table filter –A INPUT –i eth0 –p icmp - -icmp-type echo-request –m limit - -limit 5/minute - -limit-burst 10 –j ACCEPT
iptables - -table filter –A OUTPUT –o eth0 –p icmp - -icmp-type echo-reply –j ACCEPT

iptables –A FORWARD –p icmp –m state - -state ESTABLISHED,RELATED -j ACCEPT
iptables –A FORWARD –p icmp –m state - -state NEW –i ! eth0 -j ACCEPT

iptables --table filter --flush
iptables --table filter --delete-chain
iptables --table filter --zero
iptables --table nat --flush
iptables --table nat --delete-chain
iptables --table nat --zero
iptables --table mangle --flush
iptables --table mangle --delete-chain
iptables --table mangle --zero
iptables --table filter --policy INPUT DROP
iptables --table filter --policy OUTPUT DROP
iptables --table filter --policy FORWARD DROP
iptables --table nat --policy PREROUTING ACCEPT
iptables --table nat --policy POSTROUTING ACCEPT
iptables --table nat --policy OUTPUT ACCEPT
iptables --table mangle --policy PREROUTING ACCEPT
iptables --table mangle --policy INPUT ACCEPT
iptables --table mangle --policy FORWARD ACCEPT
iptables --table mangle --policy OUTPUT ACCEPT
iptables --table mangle --policy POSTROUTING ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

iptables-t nat –A PREROUTING –I eth0 –p tcp –dport 80 –j DNAT –to 192.168.20.10
iptables –t filter –A FORWARD –p tcp –m state –state ESTABLISHED –j ACCEPT
iptables –t filter –A FORWARD –p tcp –dport 80 –m state –state NEW –i eth0 –j ACCEPT

Lokaal verkeer toestaan:
iptables -t filter -A INPUT -s 127.0.0.1 -i lo -j ACCEPT
iptables -t filter -A OUTPUT -d 127.0.0.1 -o lo -j ACCEPT

Limiteren van pings naar de local host:
iptables -t filter -A INPUT -i eth0 -p icmp --icmp-type echo-request -m limit --limit 11/minute --limit-burst 15 -j ACCEPT
iptables -t filter -A OUTPUT -o eth0 -p icmp --icmp-type echo-reply -j ACCEPT

Logging:
iptables --t filter -A INPUT -j LOG --log-prefix "Toekomende pakket"

Verkeer tussen pc en router:
iptables -t filter –A INPUT –s xxx.xxx.x.x/xx –d xxx.xxx.x.xxx –i eth1 –j ACCEPT
iptables -t filter –A OUTPUT –s xxx.xxx.x.xxx –d xxx.xxx.x.x/xx –o eht1 –j ACCEPT

iptables -t filter –A INPUT –s xxx.xxx.x.x/xx –d xxx.xxx.x.xxx –i eth2 –j ACCEPT
iptables -t filter –A OUTPUT –s xxx.xxx.x.xxx –d xxx.xxx.x.x/xx –o eht2 –j ACCEPT

Internet toestaan voor LAN:
iptables -t filter -A FORWARD –i eth0 -p tcp --tcp-flags SYN,ACK,RST,FIN SYN,ACK -j ACCEPT
iptables -t filter -A FORWARD –i eth1 -p tcp --tcp-flags SYN,ACK,RST,FIN SYN -j ACCEPT
iptables -t filter -A FORWARD -p tcp --tcp-flags SYN,ACK,RST,FIN ACK -j ACCEPT
iptables --table filter -A FORWARD -p tcp --tcp-flags SYN,ACK,RST,FIN RST -j ACCEPT
iptables --table filter -A FORWARD -p tcp --tcp-flags SYN,ACK,RST,FIN ACK,FIN -j ACCEPT
iptables -t filter -A FORWARD -p udp -m state --state ESTABLISHED -j ACCEPT
iptables -t filter -A FORWARD -p udp -m state --state NEW -i ! eth0 -j ACCEPT

Services voor DMZ:
iptables-t nat –A PREROUTING –I eth0 –p tcp –dport 80 –j DNAT –to xxx.xxx.x.xx
iptables –t filter –A FORWARD –p tcp –m state –state ESTABLISHED –j ACCEPT
iptables –t filter –A FORWARD –p tcp –dport 80 –m state –state NEW –I ! eth0 –j ACCEPT

This is very specific to mostly one command. You should try typing "man iptables" , which should give you a description of the command.
http://linux.die.net/man/8/iptables
I'm not sure if anyone will respond to your request for their assessment of "consequences" of these many permutations of the command iptables. ... Maybe you will get lucky.

Good luck.