Greetings,
Recently, I completed setting up an FC2-enabled server as a home gateway.
Its connection to the Internet is by way of Verizon's PPPoE DSL. The external Westell modem connects to eth0; the home LAN connects to eth1.
Everything seems to be communicating correctly. The concern I have and the request I make of the list is to review the iptables setting for the gateway.
Stock FC2 Iptables looks like this: root@leeloo ~> iptables-save # Generated by iptables-save v1.2.9 on Sun Aug 29 17:06:53 2004 *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [20310127:17271169167] :RH-Firewall-1-INPUT - [0:0] -A INPUT -j RH-Firewall-1-INPUT -A FORWARD -j RH-Firewall-1-INPUT -A RH-Firewall-1-INPUT -s 127.127.1.0 -p udp -m udp --sport 123 --dport 123 -j ACCEPT -A RH-Firewall-1-INPUT -i lo -j ACCEPT -A RH-Firewall-1-INPUT -i eth0 -j ACCEPT -A RH-Firewall-1-INPUT -p icmp -m icmp --icmp-type 255 -j ACCEPT -A RH-Firewall-1-INPUT -p esp -j ACCEPT -A RH-Firewall-1-INPUT -p ah -j ACCEPT -A RH-Firewall-1-INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 21 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited COMMIT # Completed on Sun Aug 29 17:06:53 2004
I've amended it; the lines I've added are preceded by >>> and ended w/ <<<:
# Generated by iptables-save v1.2.9 on Sun Aug 29 17:08:40 2004 *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [10797:1210790] :RH-Firewall-1-INPUT - [0:0] -A INPUT -j RH-Firewall-1-INPUT -A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -s 127.127.1.0 -p udp -m udp --sport 123 --dport 123 -j ACCEPT <<<
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -i eth1 -j ACCEPT<<<
-A RH-Firewall-1-INPUT -p icmp -m icmp --icmp-type 255 -j ACCEPT -A RH-Firewall-1-INPUT -p esp -j ACCEPT -A RH-Firewall-1-INPUT -p ah -j ACCEPT -A RH-Firewall-1-INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 21 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m state --state NEW -m tcp --dport 53 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited COMMIT # Completed on Sun Aug 29 17:08:40 2004
Everything below was added to stock FC2 Iptables settings<<<
# Generated by iptables-save v1.2.9 on Sun Aug 29 17:08:40 2004 *nat :PREROUTING ACCEPT [11662:691042] :POSTROUTING ACCEPT [97:5735] :OUTPUT ACCEPT [96:5659] -A POSTROUTING -s 192.168.1.0/255.255.255.0 -o ppp0 -j MASQUERADE COMMIT # Completed on Sun Aug 29 17:08:40 2004
End addition <<<<
I run a standalone server on an ISP loaded w/ FC2 and running the stock Iptables configuration. There doesn't seem to be any security problems.
The biggest hurdle was getting machines on the home network making requests through the gateway; initially, no web, ssh, or ftp requests were possible using domain names. They could only be made using explicit ip addresses.
Once I added
-A RH-Firewall-1-INPUT -i eth1 -j ACCEPT<<<
service requests to the internet using domain names began to work correctly.
My concern is how exposed/vulnerable is the above gateway configuration?
Much thanks for your help!
Max Pyziur pyz@xxxxxxxxx
-- end of forwarded message --
