I can't seem to get my head around this (hopefully) simple problem. I have 1 brocade and a Mikrotik router both connected each other have an IP address from the a /28 Public facing subnet. The brocade router is also connected to a switch where the servers are connected (LAG/port-channel). That server (VM on ESX) has a Public IP address from the same /28 subnet. I can ping 23.128.xxx.1 (brocade) from the VM which is also the default gateway for the VM and I am able to get out on the internet. But when I try to ping 23.128.xxx.2 which is the IP address of Mikrotik router, I can't do that from the VM. I get Network unreachable straight away. Trace shows timeout after brocade. 23.128.xxx.1. Though I can ping 23.128.xxx.1 from Mikrotik just fine.

On the other hand I can ping brocade from Mikrotik but can't ping the VM from Mikrotik either. This all is in the same VLAN. Interestingly, I have 2 other VLANs configured the exact same way and the only difference is the VLAN id and the subnet which is /27 in the other case. That just works fine. Been trying to figure this out for so many hours can't seem to figure out anything. What can be the issue here why can't I ping Mikrotik from the VM?

Here is a network flow I have;

VM (23.128.XXX.4/28) -> Switch (LAG) -> Brocade (23.128.XXX.1/28) -> MIkrotik (23.128.XXX.2/28)

Appreciate any inputs.

  • Pls send your mikrotik config
    – Arash
    Mar 10 '18 at 8:19
  • If you are from Mikrotik, take a look at ticket 2018021222002041
    – NBhatti
    Mar 10 '18 at 14:13
  • Config here gist.github.com/nbhatti/7facd5d3891314be2c6e1d2b70289a3f anyway
    – NBhatti
    Mar 10 '18 at 14:18
  • Turns out to be adding a static route in Mikrotik add distance=1 dst-address=23.128.XXX.3/32 gateway=23.128.XXX.1 fixes the problem. But I can't understand where my default gateway on Mikrotik is already 23.128.XXX.1. Why do I still have to define a static route?
    – NBhatti
    Mar 10 '18 at 20:41

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