I am newbie to networking and trying to ping from bridge interface to another interface configured with different subnet IP address.

I am trying these configuration in oracle virtual BOX VM running with Ubuntu 16.04.

I have three interfaces eth0, eth1, eth3. In which eth0, eth1 are part of bridge br0. The bridge br0 is configured with IP address as

The another interface eth3 is configured as

When I am trying to add route it fails as Network unreachable. ip add default via dev br0

I would need to : ping -I br0 ->>>> But fails.

In oracle virtual box VM, these interfaces are configured as internal network ports (inet).

brctl show
bridge name bridge id       STP enabled interfaces
br0     8000.0800275f7d3e   no      eth0
ifconfig eth3
eth3      Link encap:Ethernet  HWaddr 08:00:27:f9:c1:a8  
          inet addr:  Bcast:  Mask:
          inet6 addr: fe80::a00:27ff:fef9:c1a8/64 Scope:Link
 ifconfig br0
  br0       Link encap:Ethernet  HWaddr 08:00:27:5f:7d:3e  
          inet addr:  Bcast:  Mask:
          inet6 addr: fe80::a00:27ff:fe5f:7d3e/64 Scope:Link

virtualBox:~# ip route add default via dev br0
**RTNETLINK answers: Network is unreachable****

VirtualBox:~# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface       U     0      0        0 br0     U     1000   0        0 eth3   U     0      0        0 eth3   U     0      0        0 eth2

When I am trying to ping from bridge interface it is failed. Any ideas how to resolve this issue.

Network Diagram

  • Is the IP forwarding enabled in the kernel parameter net.ipv4.ip_forward? – Mikhail Khirgiy Mar 9 '18 at 4:15

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