warpme írta:
Hi *
I just try setup firewall. Config is following:
Desktop Firewll
(192.168.1.1) ------Eth0 Eth1(91.189.74.10)---------ISP
Script below is working OK for all LAN hosts, but not for for firewall PC itself (i tested it with i.e. ping www.ibm.com)
Commenting line "iptables -P INPUT DROP" allows to ping from firewall, but it effectivelly turning off firewall....
It is probably simple error - but I can't find where it is...
Can somebody verify thid script and tell me what is wrong ?
thx in advance
#Config area BEGIN--------------------------------------------------------------
LAN_intf=eth0
LAN_subnetwork=192.168.1.0/255.255.255.0
WAN_intf=eth1
WAN_ip=91.189.74.10
Open_WAN_TCP_ports=20,21,80,500,1352,4500
Open_WAN_UDP_ports=500,1352,4500,5060
Open_WAN_RTP_port_range=7070:7080
#Config area END----------------------------------------------------------------
#--Flushing all iptables tables-------------------------------------------------
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
#--Setting up SNAT for outgoing to WAN DATA connections------------------------
iptables -t nat -A POSTROUTING -s $LAN_subnetwork -o $WAN_intf -j SNAT --to-source $WAN_ip
I would write like this:
iptables -t nat -A POSTROUTING ! -s $WAN_ip -o $WAN_intf -j SNAT
--to-source $WAN_ip
#--Allowing self access by loopback interface----------------------------------
iptables -A INPUT -i lo -p all -j ACCEPT
"-p all" not needed... And I would rather set up the OUTPUT rule than
the INPUT rule because the "lo" interface only accepts connections from
itself... if a new connection is made then first step is to send OUT
something to the other host... :D
iptables -A OUTPUT -o lo -j ACCEPT
#--Allowing local access to LAN------------------------------------------------
iptables -A INPUT -i $LAN_intf -p all -j ACCEPT
no need for "-p all"
#--Allowing WAN incoming traffic form already established connections----------
iptables -A INPUT -i WAN_intf -m state --state ESTABLISHED,RELATED -j ACCEPT
#--Allowing WAN incoming traffic for desired services--------------------------
#Open WAN TCP ports
iptables -A INPUT -p tcp -i $WAN_intf -m multiport --dport $Open_WAN_TCP_ports -j ACCEPT
#Open WAN UDP ports
iptables -A INPUT -p udp -i $WAN_intf -m multiport --dport $Open_WAN_UDP_ports -j ACCEPT
#Open VoIP UDP port ranges
iptables -A INPUT -p udp -i $WAN_intf --dport $Open_WAN_RTP_port_range -j ACCEPT
For "ping" you need the following line:
iptables -A INPUT -p icmp -j ACCEPT
#--Drop all other incoming connection. Only above will be allowed-------------
iptables -P INPUT DROP
