Can't reach host on local network, but not over WAN. Odd details included.

[bbabbmcl4214]

So as the title says, I've got some really odd things going on to seemingly random workstations. Thankfully only a couple so far.

So I can't reach these workstations outside of their physical location. From their switch I can ping them. I've used extended commands to ping from other interfaces on that switch to make sure routing isn't getting in the way with 100% success. I can reach that workstation from all VLANS on that switch. 

From other locations I can't reach that workstation. Pings fail, Traceroutes fail. In fact it doesn't look like traceroutes even leave these other switches. What's odd about that is that I can ping and traceroute to a different IP address on the same subnet as the effected machine so it doesn't look like routing or ACLs are in the way. 

I've checked DNS to make sure that was correct and it was.

Any help/ideas would be greatly appreciated. 

Thanks!

[Mohsin Alam]

Can you post a topology ( simple one ) to start with?

Also what switch is it exactly? can you set up a span or a EPC to check the flow?

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[bbabbmcl4214]

The topology is dead simple. All stations connect to 4 C9300-48U switches which are stacked (so one single logical switch). 1 port is a routed port which goes to our WAN. 

I haven't set up a SPAN session yet, but I can. I can see plenty of traffic on that port by looking at the counters on 'sh int gig x/x/x'. It's sending and receiving traffic on the local network where most of our servers are staged anyway. 

This port does have a phone attached to it as well, using a voice vlan.