Networking – Why can’t I ping any computers on the same hub

hubipnetworking

I'm having some interesting problems pinging machines, with the end goal to have Computer B SSH into Computer C. The specific error message I get from ping is "Destination Host Unreachable", and ssh returns "No Route To Host".
To start, the following is my network topology:

Router (192.168.1.1)
   |
   |---- Computer A (192.168.1.2)
   |
   |---- Hub
          |
          |---- Computer B (192.168.1.3)
          |
          |---- Computer C (192.168.1.4)

Computer A is able to ping both Computers B and C, and vice-versa. However, Computer B cannot ping Computer C, and vice-versa. The IP addresses are shown above, and the network configuration for each machine is:

Gateway - 192.168.1.1
Netmask - 255.255.255.0

Why am I unable to have Computer B communicate with Computer C in this setup?

Best Answer

Hub is not a Hub, it is a switch with different segment VLANs configured on each interface. Router is stripping the 8021Q tags and allowing routed communication back across to a single vlan.

If the router were replaced with a switch you wouldn't see the communication to and from A - B, A- C.

The reason why you are getting destination unreachable is because there is no ip on that vlan segment the ip of B on C's segment.

Hubs are multi-port repeaters. There is no way a simple hub can block this communication, this is not a hub but a misconfigured switch.

-- or Hub is busted.. lol.

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