Unable to ping single IP on a subnet but only from certain devices

[jason2g6114]

I have (2) HP 8206's that I am using as my core switches, (2) 4451 Cisco ISR's that I am using as my Core Routers. They are connected with Port Channels and LACP Distributed Trunking for full redundancy. This configuration has been working fine for the last year since I installed it. The other day we had a server that is running in our VMWare environment that became inaccessible by a hand full of my branches. The branches are on a MPLS Wireless infrastructure. I am using OSPF for internal dynamic routing and BGP for the WAN side. All the branches are configured the same and a handful cannot ping this IP address. I have done trace routes and the last IP from either side is the Core router. There is only one access list on this device and that is an access list for a route map to split internet traffic. This ACL has been verified and is exactly the same and untouched for 7 months now. Can anyone please provide some additional guidance to troubleshoot this issue. Thanks.  

[Philip D'Ath]

If the last IP that responded is the Cisco router then the issue is between that router and the next hop.

Try unplugging all but one member from your port channels (so there is only one path) and see if the issue changes.

Otherwise you are going to need to track the path between the routers and there next layer 3 hop to see where the packets are being mis-directed.

[jason2g6114]

I have limited the connection to only one path between the Core Router and Core Switch. No change in the connectivity. Is there a debug that I can turn on to see what the router is doing with packets destined or sourced from a specific IP? Thanks.