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Gecko68
07-06-2001, 06:04 PM
There's this project i got thrown into that's making my mind turn to jelly. If anyone wants to take a stab at helping me, it will be more than appreciated. Here goes the long and torturous explanation:

A remote office (eventually 7 of them) running a private 192.168.x.x network uses a compatible systems router over a frame relay to the central office cisco 2600 router. The Cisco, which also happens to have the public IP given to us by the ISP, gets directly plugged to the linux box external NIC (eth0)which also has a public IP. (basically the Cisco is the gateway out to the public as well as the collection point for the frame relays) The internal NIC (eth1, private 192.168.x.x) of the linux box then is patched to a big 10/100 switch, allowing the central office's computers to be firewalled by the linux box, and to browse using NAT, or masqerading as it's known in linux. (i think).
Now, in theory, this system is to allow the remote offices to also be behind the linux firewall as far as internet access goes, and be able to use the resources at the central office (citrix server, printers, fax server, other things on the private 192.168.x.x ).

On the linux box, eth1 uses eth0 as a gateway, eth0 uses the cisco as a gateway. The workstations use the linux eth1 as a gateway, thus establishing internet connectivity from the private side in the Central office.

right now, i can go to a remote office and ping to the internal IP of the linux box, but not any of the other resources at the central office. they cannot browse to the internet.
The central office computers use the internet, and can ping to the remote workstations in the other offices.

*whew!*

Is my problem a routing issue, or is it a firewall issue? The system is RedHat 7.1. which means that either iptables or ipchains can be used for firewalling. I currently am using, in the gnome gui, "firewall-tools from the system menu. I think it uses ipchains to do this.

Again, any comments, explanations, or ideas are welcome. Just trying to brainstorm and figure this out. Thanks!

Jorden

jumpedintothefire
07-06-2001, 08:53 PM
Need a bit more info.
What firewall rules do you have in place now?
ip address of all the networks?
the output of route -n?

the layout of your setup is:

internet> {HOMErouter} > linux box > home lan
frame relays > {HOMErouter}

frame relays < remote lans


With all the frame relays and the linux box hooked in to the HOMErouter


correct?


Just want to get the layout down in my head.
What is the result of a trace route from one of your home lan machines to the remote lan machines? And from the remote lan to the home lan?

I think you may have both routing and firewall issues. I think your trying to do forwarding for the remote lans and MASQ for internet access, but your rules are just for MASQ.(hence the one way access)

Darn I'm not good at drawing :rolleyes:

[ 06 July 2001: Message edited by: jumpedintothefire ]

Gecko68
07-12-2001, 01:38 AM
:D AHA!!!!

I fixed the problem without having to go into a very difficult thing. I actually got to look at the router, and noticed that it had 2 ethernet ports. They were only using one of them, which was crazy.

I had them set the other one with a private IP, and send all the frame relay traffic to that NIC (eth0/1) so it was easy to do firewalling/nat/masq after that. the remote offices can browse, and use the citrix app server in the central office over their frame relay connections, instead of their 56k dialup modem connections like before.
Here's a sort of diagram of what it's like now:

|----------------| |--------------------|
| internet cloud | | Frame Relay Cloud |
|________________| |____________________|
| |
| |
cisco pub NIC cisco priv NIC
| |
| |__________
| |
|________________________________| |
| | | |
| linux pub nic | linux priv NIC | |
| | | |
|___________<nat/masq>___________| |
| |
____________________| |
| |
| __________________|
| |
|-----------------------------------|
| |
| HP Procurve 4000M Switch |
| |
-------------------------------------

Gecko68
07-12-2001, 01:39 AM
never mind. i can't even think of how to format that just now. so it looks right. email me if you want and I'll send you the notepad file. :)