Help - Search - Members - Calendar
Full Version: Please Help!, Rh Linux 9 Using As A Router
Linuxhelp > Support > Technical Support
Helo all,

I am not new to linux, I have used RH 6 through 8 as a gateway router with two NICS in the past without any probs.

Now my friend had my set up a linux box with RH 9 and 3 NICS.... One NIC (eth0) goes to cable modem, and eth1 and eth2 are cross over cables going to his other two wind0ze boxs....

Here's my prob.

I haven't played with linux in a while and I can't seem to get this all going...

I enable ipv4 forwarding in sysctl, but I can't even ping out on the internet yet ....

The main problem to me seems that the linux box doesn't know which is the default NIC that goes out to the internet...
after numerous boots it at one time went online fine, but never again. I've flushed the iptables and removed the firewall and still nothing. Eth0 is going to the cable modem, so I ended up scraping dhcp for that card and set up the connection static and used all the information from a win2k ipconfig /all and got all the goodies like ip addy, agatewaye, dns etc.... hardcoded eth0 and tried to ping over the internet, destination network unreachable?

After doing a "route -n" it looks like it's routing everything to the wrong NIC, eth2 UF
I need the UG default gateway to be the ISP gateway for eth0 .... I've tried playing with the route -add and route -del
without any success, now I have two default gateway's setup... I've spent ALL day on this.... Isn't there a way to flush the route tables completely and rebuild them ? or a GUI program that I can use?

I've used ipfwadm and ipchains in the past on previous RH distro's so iptables shouldn't be that hard to figure out.

But what's killing me as I can't get this going.... When I try to ping an internet ip, it's trying to ping off of one of the cards that's connected to the LAN, instead of the eth0 that's going to the internet... Im geussing this is all sorted with the rouiting tables...

Maybe because I forgot how to set up a basic network using two NICS... Question , when statically setting up a NIC on linux to be connected to a LAN on the 192.168 range what should be the gateway address of that NIC? should it be set to the same IP of the NIC? or the gateway of the internet ISP?


ipaddress :

and then set up the other computer on lan to have ip address of for example and point the gateway of that computer to the IP of eth1.


ipaddress :

I know Im all over the place here, but I'd sure appreciate any help on this!
Im thinking I should have installed RH 8 instead of RH 9. I don't like the way iptables is set up,
and I've set up ipchains using RH 8 within an hour... Unless anybody here has some input ?
My advise is:

1. I don't recommend using RH8 or RH9 on the boundry ... there are no more security updates for either version from RedHat .. and when new security issues are found, there will be no updates. This will make that gateway box susceptible to know security vulnerabilites. I would recommend CentOS or WBEL ... they are very similar to RedHat 9 (they are actaully RHEL 3 AS Clones).

2. Make sure what you think is eth0 really is ... if you have GUI, you can use redhat-config-network to look setup the default gateway, etc. You might try removing all but one eth card ... get that working with DHCP first, then add the other cards.

3. Use this script to do the firewall ... I use it on many boxes.
Thanks for the response,

Yeah I was thinking about removing all nics and start with just eth0 to internet, and build on from there. I was checking in to that white box linux.... verry interesting, thanks for the advice, I think I might just try this distro, as if it is as you say and it is based of RH and has the support like EL then Im in! I've never really tried other linux distro's, been a hardcore RH user since RH 6... Looks like old habiits wil die hard, and I will try this white box distro...

Quick question though, It looks like there two version, source and binary... Are these iso discs bootable and can they install like RH using anaconda? or are these just source files? Im guessing I want to download the binary iso's?

Thanks again for your help,

The 3 binary discs are just like the 3 RH9 binary discs ... boot from the binary CD-1. You don't need the source ISOs to do installs.

The is no real difference between CentOS and WBEL ... Although CentOS 3.3 is a newer version (Includes RHEL AS 3 update 3 ... WBEL respin1 is RHEL AS 3 update 2) .

After install, use yum to upgrade, and after updating, both are the same. (But there are fewer packages that need upgrading after CentOS install than WBEL install).

You can pick a mirror for downloading CentOS from here ... after selecting the closest mirror, go to centos-3/3.3/isos/i386/ and download the 3 binary (non src) ISOs.

You can also select a WBEL mirror from here and download their 3 binary ISOs.

It seems that there are more (and faster) mirrors for CentOS at present.

I use both distros, either will work fine. chrisw (another admin here) like CentOS better.

Here is a guide for a minimal install of either distro. This includes updated /etc/yum.conf files to do the after install upgrades.
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2017 Invision Power Services, Inc.