Re: Trying to setup two ethernet cards with two websites

Roy Sigurd Karlsbakk <roy@xxxxxxxxxxxxx> · Tue, 31 Dec 2002 19:49:45 +0100

On Tuesday, December 31, 2002, at 05:29 PM, JUSTIN GERRY wrote:

I am attempting to setup two websites with two ip address, each one on 
a

different ethernet card/interface.

It only seems to work for the first rule (first listed ip address) that

gets matched up, so I can get one website to work but not the other. 
How

do I write this so it covers both address and allows httpd to go to

either interface or either address? Can I write a single rule to match 
a

range of ip addresses (.93 and .94) instead of writing one for each

individual address?

This is what I have so far for testing.....

IF1="eth0"

IF2="eth1"

IP2="172.30.12.93"

IP1="172.30.12.94"

UNPRIVPORTS="1024:65535"

iptables -F

iptables -P INPUT DROP

iptables -P FORWARD DROP

iptables -P OUTPUT DROP

iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

the two below...

iptables -A INPUT -i $IF1 -p tcp --sport $UNPRIVPORTS -d $IP1 --dport
80 -m state --state NEW -j ACCEPT
iptables -A INPUT -i $IF2 -p tcp --sport $UNPRIVPORTS -d $IP2 --dport
80 -m state --state NEW -j ACCEPT

...are included in these two, so you won't need both. You probably 
don't want those below, as they accept anything regardless to state.

iptables -A INPUT -i $IF1 -p tcp --sport $UNPRIVPORTS -d $IP1 --dport
80 -j ACCEPT
iptables -A INPUT -i $IF2 -p tcp --sport $UNPRIVPORTS -d $IP2 --dport
80 -j ACCEPT

are these really nessecary? with -P DROP, this'll deny any outgoing 
connections at all, regardless of protocol. It'll even drop ICMP 
packets, something you probably don't want.

iptables -A OUTPUT -o $IF2 -p tcp ! --syn -s $IP2 --sport 80 --dport
$UNPRIVPORTS -j ACCEPT
iptables -A OUTPUT -o $IF1 -p tcp ! --syn -s $IP1 --sport 80 --dport
$UNPRIVPORTS -j ACCEPT

To allow for multiple hosts in a rule, you can specify a mask (or 
number of bits). For instance:

# iptables -s 10.0.0.0/31

will match 10.0.0.0 and 10.0.0.1. .93 and .94, however, overlaps this 
and needs to be allowed for specifically.

so - try first with -P OUTPUT -j ACCEPT, and no rules in the OUTPUT 
chain. It shouldn't be any problem then.

roy