# Linux router help

## BlueFusion

Hi folks.  I have been using a Dell PowerEdge 2650 for storage, processing, and my router for some time now.  I read up on jumbo frames recently and wanted to enable them for my home network.  I have several devices that are Gigabit/Jumbo Frame capable and some that aren't.  For example, my Linksys WRT54G and all wireless devices are not JF compatible.  I decided to split the gigabit and the non-gigabit on two seperate subnets.  They both go through my Netgear smart switch, but I am using a port-based VLAN to seperate the subnets.  So far the subnets work fine and access through the server (router) to access the internet is fine.  I am not able to access devices on the different subnets, however.

Here's the scenario:

On my router, I have:

eth0 = 10.1.2.0/24

eth1 = Modem

eth2 = 10.1.1.0/24

What do I have to do to allow my wireless laptop (10.1.2.10) to access my desktop (10.1.1.5)?

I am attaching my complete iptables settings, too.  I don't think it's a firewall issue, but maybe it is.  I figured the router would just forward traffic to the appropriate port (subnet) without any static route changes on any of the devices.  Currently, all I get when trying to ping a device on the other subnet, I only get Destination host is unreachable

 *Quote:*   

> #!/bin/sh
> 
> IF_WAN="eth1"
> 
> IF_LAN_GIG="eth2"
> ...

 

route -n on my router:

```
supernova kernels # route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

0.0.0.0         xx.xx.xx.1     0.0.0.0         UG    2      0        0 eth1

10.1.1.0        0.0.0.0         255.255.255.0   U     0      0        0 eth2

10.1.2.0        0.0.0.0         255.255.255.0   U     0      0        0 eth0

xx.xx.xx.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1

127.0.0.0       127.0.0.1       255.0.0.0       UG    0      0        0 lo
```

ifconfig -a:

```
eth0      Link encap:Ethernet  HWaddr 00:0d:56:b9:28:8f  

          inet addr:10.1.2.1  Bcast:10.1.2.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:29209 errors:0 dropped:12 overruns:0 frame:0

          TX packets:47359 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:2592710 (2.4 MiB)  TX bytes:11472394 (10.9 MiB)

          Interrupt:28 

eth1      Link encap:Ethernet  HWaddr 00:0d:56:b9:28:90  

          inet addr:xx.xx.xx.xx  Bcast:xx.xx.xx.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:105842 errors:0 dropped:0 overruns:0 frame:0

          TX packets:61922 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:115216616 (109.8 MiB)  TX bytes:6649036 (6.3 MiB)

          Interrupt:29 

eth2      Link encap:Ethernet  HWaddr 00:08:02:28:f1:3b  

          inet addr:10.1.1.1  Bcast:10.1.1.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:9000  Metric:1

          RX packets:5235 errors:0 dropped:15 overruns:0 frame:0

          TX packets:5397 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000 

          RX bytes:593861 (579.9 KiB)  TX bytes:4567136 (4.3 MiB)

          Interrupt:20 

lo        Link encap:Local Loopback  

          inet addr:127.0.0.1  Mask:255.0.0.0

          UP LOOPBACK RUNNING  MTU:16436  Metric:1

          RX packets:3642 errors:0 dropped:0 overruns:0 frame:0

          TX packets:3642 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:0 

          RX bytes:521158 (508.9 KiB)  TX bytes:521158 (508.9 KiB)
```

----------

## BillWho

A real long shot

route add -host  10.1.1.5 gw 10.1.2.1

route add -net 10.1.0.0 netmask 255.0.0.0 gw 10.1.2.1

----------

## Veldrin

@OP: can you post the actual running iptables config? iptables -nvL

@BillWho: no additional routing is needed. both networks are directly attached to the router, and the respective hosts can use the default route to get to the router, which will handle any further routing. 

V.

----------

## BlueFusion

I gave up on it.  It seemed like more trouble than it was worth for the slight increase in NFS/rsync performance.  Maybe once I get more devices that support JF, I'll try again.

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## Mistwolf

Your subnet masks are wrong.  They are blocking the subnets from accessing each other.  Correct subnet mask should be 255.255.0.0 or, if you really want, 255.255.252.0.  That way, it is all considered one network.

Hope this helps.

Dario

----------

## py-ro

Did you even enable forwarding?

```
cat /proc/sys/net/ipv4/conf/all/forwarding
```

@Mistwolf: You are wrong, too.

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## BlueFusion

I did have forwarding enabled as the server is currently working as my NAT router.

Mistwolf, are those changes necessary on the router or each computer?

----------

