troubleshooting Question

Cross-Network Traffic

Avatar of Creden Wigal
Creden Wigal asked on
22 Comments2 Solutions307 ViewsLast Modified:
For starters, I am new to this organization and inherited a mess of a network.  We have a WatchGuard Firebox M500 for routing/firewall and we have seven main switches.  The organization started out with a /24 network and outgrew the available IP addresses  a while back so they created a new subnet and both are still in use today.  We are slowing phasing out the /24 network...but it will take a while.

Four switches are on the original network (network 1) and three switches on network 2.  They are connected to the pertinent port on the WatchGuard to route traffic between them.  VLAN's are not used, just the different subnets.  I have looked at the logs on the WatchGuard and I can see it passing traffic between the two networks.

I found a cable connecting one switch on network 1 to a switch on network 2...and these are on different subnets.  I disconnected that cable and users instantly lost connection with their servers (servers are almost all on network 1 and users PC's/Mac's are on network 2).  Equipment is all setup with correct gateway, dns, etc.  

This is a 24/7 unfortunately I don't have very long to take the connection down and do any testing...and I have looked at everything I could think of as to why they lose connection when I disconnect this cable and come up with nothing.

I was hoping someone might be able to help me figure out how I can disconnect that cable and have the network stable going through the WatchGuard, like it should be.

Let me know what you need to see configuration-wise and I'll do my best to give as much info as you need.

Thank you!
Steve Knight
IT Consultancy

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