Routing issues

ptulpen · 11-07-2013, 10:20 AM

Hello everyone,
I try to setup a VirtualBox VM where everything internal is routed to a bridged NIC, whereas all other traffic (surfing) is router to a second NIC configured with NAT.

current setup:

Code:

eth0      Link encap:Ethernet  HWaddr 08:00:27:BB:6F:85  
          inet addr:10.16.6.232  Bcast:10.16.7.255  Mask:255.255.254.0
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

eth1      Link encap:Ethernet  HWaddr 08:00:27:E9:F8:FC  
          inet addr:172.16.0.15  Bcast:172.31.255.255  Mask:255.240.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5388 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5355 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2692118 (2.5 Mb)  TX bytes:673398 (657.6 Kb)

current routing:

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.16.0.2      0.0.0.0         UG    0      0        0 eth1
10.16.0.0       10.16.6.1       255.255.0.0     UG    0      0        0 eth0
10.16.6.1       0.0.0.0         255.255.255.255 UH    0      0        0 eth0
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 eth1
172.16.0.0      0.0.0.0         255.240.0.0     U     0      0        0 eth1

172.16.0.2 is the gateway of the NAT, 10.16.6.1 the gateway of the bridged network.

But when i ping something in the 10.16.x.x area, i get no response.
via ifconfig you can see the the packets are not even sent.

Can you please hint me where my mistake is?

Best regards,
Peter

pingu · 11-07-2013, 01:18 PM

Haven't you mixed up the subnet masks here (is there a reason for why you don't use "standard" netmasks 255.255.255.0 / 255.255.0.0)?
You have netmask 255.255.254.0 on eth0, but in routing table 255.255.0.0.

ptulpen · 11-08-2013, 03:18 AM

Hi,
Well, my idea was to reach the whole area 10.16.0.1-10.16.255.255 with this rule (10.16.6.1 knows about the other networks as well)
But I am not sure if this is the way to get this.

Best regards,
Peter

ptulpen · 11-11-2013, 02:24 AM

I found the issue myself: I wwas missing a line for the subnet itself. so adding this line did the trick

Code:

10.16.6.0    0.0.0.0    255.255.254.0  U  0  0  eth0

Best regards,
Peter