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Old 06-23-2010, 08:51 AM   #1
Registered: May 2008
Location: India
Distribution: Ubuntu 10.04, CentOS
Posts: 179

Rep: Reputation: 27
Question Linux as a route/firewall

Hi All,

OS= CentOS 5.5 64bit

Need help in setting up a Linux as a route/firewall.

My ISP has given me WAN and LAN public IPs

WAN IPs (2 IPs)

LAN IPs (6 IPs)

My ISP told me that is routed to cause this are wan IP and cannot be used directly so we have to do routing to get access to

I have no knowledge of WAN IPs
Do I need to have a WAN port on my linux firewall? Or how do I do the setup?
Old 06-23-2010, 12:21 PM   #2
LQ Newbie
Registered: Jun 2008
Location: DaeJeon,Korea
Posts: 5

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Because of my poor english,my answer may have some fault.

See your modem,then it may have RJ-45port,then you have no need of complex design.

ISP's comment means
"Between two connection ISP's side endpoint ip is 245 and your side is 246."

One example,below command may not exactly I'm not linux user.

Eth0 : 246/30 =>can't use any other IP
eth1 : 249/29 =>can use 249~254
eth2 :

route add -net netmask eth1
route add -net netmask eth2
route add default gw

You can connect two switching hubs each eth1 and eth2

There may be some other net design,but if you need to use public clients & private clients,then seperate interface using will remove much more complex.

This style design may need some considerance about BUS I/O and inturrept mechanism.

콩글리쉬로 할려니 죽겠네::

this is Korean Alphabet.English is very hard;;;


Last edited by ggeagle; 06-23-2010 at 12:44 PM.
Old 06-23-2010, 04:14 PM   #3
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Registered: Mar 2008
Posts: 13,689

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Lans should use private IP addresses.

Last edited by jefro; 06-23-2010 at 04:15 PM.


firewall, lan, wan

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