Thanks for responding everyone. I am hopefully very close to
implementing these rules. Here is my proposed set of rules. I have a
couple of concerns but please feel free to leave input:
# First drop everything (lets you open what you want)
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP
# PREROUTING chain rules
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 80 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 443 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 21 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 22 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 25 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 953 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 993 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p udp --dport 53 -j DNAT
--to-dest 192.168.0.2
iptables -t nat -A PREROUTING -d 172.10.10.2 -p udp --dport 53 -j DNAT
--to-dest 192.168.0.2
# User-defined chain for ACCEPTed TCP packets
iptables -N okay
iptables -A okay -p TCP --syn -j ACCEPT
iptables -A okay -p TCP -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A okay -p TCP -j DROP
# INPUT chain rules
iptables -A INPUT -p ALL -i eth1 -s 192.168.0.0/24 -j ACCEPT
iptables -A INPUT -p ALL -i lo -s 127.0.0.1 -j ACCEPT
iptables -A INPUT -p ALL -i lo -s 192.168.0.1 -j ACCEPT
iptables -A INPUT -p ALL -i lo -s 172.10.10.1 -j ACCEPT
iptables -A INPUT -p ALL -i lo -s 172.10.10.2 -j ACCEPT
iptables -A INPUT -p ALL -i eth1 -d 192.168.0.255 -j ACCEPT
# Rules for incoming packets from the Internet
# Packets for established connections
iptables -A INPUT -p ALL -d 172.10.10.1 -m state --state
ESTABLISHED,RELATED -j ACCEPT
# NOT SURE IF I NEED THIS AS IT'S AN INPUT???
# iptables -A INPUT -p ALL -d 172.10.10.2 -m state --state
ESTABLISHED,RELATED -j ACCEPT
# TCP rules
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 21 -j okay
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 22 -j okay
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 25 -j okay
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 80 -j okay
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 443 -j okay
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 953 -j okay
iptables -A INPUT -p TCP -i eth0 -s 0/0 --destination-port 993 -j okay
# UDP rules
iptables -A INPUT -p UDP -i eth0 -s 0/0 --destination-port 53 -j ACCEPT
iptables -A INPUT -p UDP -i eth0 -s 0/0 --destination-port 2074 -j ACCEPT
iptables -A INPUT -p UDP -i eth0 -s 0/0 --destination-port 4000 -j ACCEPT
iptables -A INPUT -p UDP -i eth0 -s 0/0 --destination-port 953 -j ACCEPT
# ICMP rules
# FORWARD chain rules
iptables -A FORWARD -i eth1 -j ACCEPT
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
# - FORWARDS to server
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 21 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 22 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 25 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 953-j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p tcp --dport 993 -j ACCEPT
iptables -A FORWARD -i eth0 -d 192.168.0.2 -p udp --dport 53 -j ACCEPT
iptables -A FORWARD -i etho -d 192.168.0.2 -p udp --dport 953-j ACCEPT
# iptables -A FORWARD -i eth0 -d 192.168.0.2 -j ACCEPT
# OUTPUT chain rules
iptables -A OUTPUT -p ALL -s 127.0.0.1 -j ACCEPT
iptables -A OUTPUT -p ALL -s 192.168.0.1 -j ACCEPT
iptables -A OUTPUT -p ALL -s 172.10.10.1 -j ACCEPT
# NOT SURE IF THIS IS CORRECT OR NEEDED???
iptables -A OUTPUT -p ALL -s 172.10.10.2 -j ACCEPT
# POSTROUTING
iptables -t nat -A POSTROUTING -s 192.168.0.2 -j SNAT --to-source
172.10.10.2
iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to-source 172.10.10.1
Guillaume wrote:
Pascal Hambourg a écrit :
Guillaume a écrit :
I think you 2 problems in your rules:
- The chains in NAT table must not be set to drop. NO filtering in
nat table.
- You forgot to add the rules to autorise traffic coming from
eth0:0 to your internal host. After a DNAT rule, you need to
explicitely autorise the corresponding traffic.
Ab i think, I've don't read any rule related to that.
For example, you set this rule:
iptables -t nat -A PREROUTING -d 172.10.10.2 -p tcp --dport 80 -j
DNAT --to-dest 192.168.0.2
You must set this rule:
iptables -t filter -A FORWARD -i eth0:0 -p tcp -d 192.168.0.2
--dport 80 -j ACCEPT
And the same for all incoming traffics.
This is correct except for one detail : the interface eth0:0 does not
exist. It is only an alias and is not used by either the routing nor
iptables. You muse use the real interface name, eth0.
hhhmmm
Ok :-)
I never use alias on interface... :-)
Thx for correcting me
Guillaume
