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Old 07-08-2004, 01:16 AM   #1
Registered: May 2004
Location: india
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how to configure ip masquerading


My configuration is like this- RH-9 with 2 network cards. One is for internal and one is for internet. I am useing cable modem. My problem is that

1) how i will share my internet (ip masquerading and squid proxy).

please let me know asap

Old 07-08-2004, 02:22 AM   #2
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Location: Lithuania
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here you can find a lot of information
Old 07-08-2004, 04:51 AM   #3
Registered: Jun 2004
Location: Karachi
Distribution: Redhat
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Ip masquerading


well wat i have understand is that u want to shareyour internet connection to more then one system on a single line...

command is as follows

[root@localhost root] ifconfig eth0:1 netmask up

Old 07-08-2004, 06:56 AM   #4
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Registered: Mar 2003
Distribution: Fedora
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Re: Ip masquerading

Originally posted by hasnain

[root@localhost root] ifconfig eth0:1 netmask up
That would be how to give a network adapter a second (virtual) IP address.

To setup masquerading, as root enter into the commandline:

iptables -t nat -A POSTROUTING -o ethX -j MASQUERADE

You'll also need to turn on port forwarding (echo "1" > /proc/sys/net/ipv4/ip_forward) and setup forwarding rules to allow traffic to pass between the two interfaces. Something like this should work:

iptables -A FORWARD -i ethY -o ethX -j ACCEPT
iptables -A FORWARD -i ethX -o ethY -m state --state ESTABLISHED,RELATED -j ACCEPT

Where ethX is your external interface (connected to internet) and ethY is the internal interface (connected to your internal LAN).
Old 07-16-2004, 10:45 AM   #5
Registered: May 2001
Location: Madras, India
Distribution: Mandrake, Vector, Fedora, Slackware-Live, CentOS, Ubuntu, Kubuntu, PCLOS, Sabayon
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That's easy !

Just get hold of 'Firestarter' and install it.
Couple of mouse clicks and voila, you have you have your Firewall and IP Masquerade up and running.
Another ways is get to and get the firewall script from there and soon enough you'll have a Firewall and IP Masq up and running.
I can assure you no sweat at all.
But you wanna dirty your hands and write your own custom IP tables script with NAT (IP Masquerade) go right ahead. But first beef up on the IPTables HOWTO. Good starting point http://iptables-tutorial.frozentux.n...-tutorial.html
Old 07-16-2004, 10:53 AM   #6
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Location: Beautiful BC
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If your just want to configure linux to act as a Internet gateway, get a hold of SmoothWall Express 2.0. (As you are in India, the CDs accompanying the current issue of PCQuest has SmoothWall Express 2.0).

The installation and configuration are a breeze.

Last edited by ppuru; 07-16-2004 at 10:54 AM.


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