Having issue with routing one gateway to different subnets

[linuxfan27]

Hi all,


Im having a issue with routing internet traffic from my router two different subnets (vlans). Theres my setup:-


Server:

eth2 to the router
192.168.2.2 mask 255.255.255.0 gw 192.168.2.1 thats ok

eth0 to vlan2
192.168.3.1 mask 255.255.255.0 gw 192.168.2.1

eth1 to vlan3
192.168.4.1 mask 255.255.255.0 gw 192.168.2.1

Both eth0,1 are running dhcp (two scoopes) that works fine !

the output of route -n is :-

192.168.4.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.3.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1
0.0.0.0 192.168.2.1 0.0.0.0 UG 0 0 0 eth2

i have ip_forwarding on aswell, but i can ping the ip on the server running that dhcp scoope ie ping 192.168.4.1 works great but i just cant get the internet on the clients

i guess theres something im missing


any help will be great


thanks

[Rubberman]

These are not vlans, but different lans. 192.x.x.x addresses are class C networks (non-routable outside the LAN). To get a vlan (subnet), you need to have all using 192.168.1.x addresses, but set your subnet mask accordingly to how many subnets you need. In your case, each "vlan" needs its own router, then you can access the internet from each system, otherwise you need to use real subnets.

[Rubberman]

FWIW, I am currently teaching this cruft in a data communication and networking class to AT&T technicians...

[Rubberman]

One last thing you might try before restructuring your network, is to provide more complete information about your network's physical setup. My "pronouncements" originally are very general in scope, though generally true. However, as we all know, the devil is in the details!

[linuxfan27]

Hi Rub,


Sorry i didnt explain it properly.

I have a server with three nics eth2 going to the router, eth0 and 1 going to a switch with 2 vlans setup. Client are connected to the switch on a vlan which there is dhcp server running with 2 scopes for each of the nics going to vlan on the switch.

I want the server to be a router as such, which i know it can be done as there distro about that does it. I understand that 192.168.x.x is not a vlan thats where i wrote it down wrong when i typed it out.

So technically the main internet connection is eth2, but i need to route the internet though to the clients thats connected to a vlan on the switch

But i dont know where im going wrong

Thanks for your help

[Rubberman]

Ok. That's clearer now. The router is the overall network gateway to the internet. The server is the LAN router. So what is the address of the edge router (connected to eth2)? What is it's subnet mask?

[linuxfan27]

Router 192.168.2.1 mask 255.255.255.0


server

eth2 192.168.2.2 mask 255.255.255.0 internet
eth0 192.168.3.1 mask 255.255.255.0 vlan 2
eth1 192.168.4.1 mask 255.255.255.0 vlan 3


edit: i deleted the diagram that was there and just wrote it out it didnt display properly




thanks

[Rubberman]

It came out fine in the email. The main problem I see is that the "vlan"s are using 192.168.2.1 as their gateway. You need to set the gateway to 192.168.3.1 or 192.168.4.1 for the systems on each segment, depending upon the ethernet port on the server you are using. Then, set up your routing table on the server to connect each of those to 192.168.2.1 so internet requests eventually get to the edge router and onto the internet.

[linuxfan27]

Right ok, i have opened the route tab on nic 192.168.2.1 in the network manager and put destination 192.168.4.1 and mask as 255.255.255.0 and gw 192.168.2.1 then i restarted the connections and its still not working

any ideas