Strange issue single ip intermittently cannot connect to another ip

[premiertechllc]

Strange situation appears to be network related so far.  Hoping an expert can assist me.

My environment:

Satellite office (CISCO router 2851 / cisco sw c3750) ----------COMCAST EPL (FIBER)-------MAIN SITE (Cisco ROUTER 2851/Cisco 3750 switches Stacked/ASA 5525-x)

My issue:

So routers are used to route traffic between network subnets and provide for 911 telco service at eacRoutingh site.  Switches are catalyst 3750s.  I have multiple sites connecting to main site same way.  No changes on the network equip at any site. Issue is that occasionally a workstation from satellite office lets say ip is 192.168.108.100 suddenly loses connection to main site server 192.168.100.10.  The workstation suddenly cannot ping 192.168.100.10 nor connect to it via rdp/file/etc. Other workstations at Satellite offices can see the 192.168.100.10 server fine while this is occurring.  The Workstation that cannot access it can connect to other servers on the 192.168.100.x network fine when issue occurs.  If i change the workstation ip to a different 192.168.108.x address it then can ping and see the server fine.  If I reboot the routers the connection also again works from the workstation to the server.  It is not just 1 workstation nor 1 satellite office  this occurs on.  When it occurs it could be several workstations at different offices connecting to different servers at main office.   I know a bit confusing so if i can provide answers to questions ill do.  Seems like a routing table issue as when I tracert from the satellite workstation to the server it drops off right after hitting the satellite office router and never goes past that.  Could the router at the main suddenly block ip acceess from remote sites suddenly ?

[paul driver]

Hello

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@premiertechllc wrote:

Satellite office (CISCO router 2851 / cisco sw c3750) ----------COMCAST EPL (FIBER)-------MAIN SITE (Cisco ROUTER 2851/Cisco 3750 switches Stacked/ASA 5525-x)

Other workstations at Satellite offices can see the 192.168.100.10 server fine while this is occurring.  The Workstation that cannot access it can connect to other servers on the 192.168.100.x network fine when issue occurs. 

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When this occurs, do the rtrs/asa have the correct arp entries for the effected host(s), Is it possible you are experiencing duplicate address allocation?

Is there anything being logged in the rtrs/fw buffer to indicate the root cause?

[Richard Burts]

I agree that if changing the remote host IP address to a different address then make the host able to reach the server that it suggests a problem with duplicate addressing.

I have a question about this: when the remote host is having problems reaching that server is that remote host able to reach other resources in the same subnet as the server? Is that remote host able to reach other resources in other subnets at the main office? Is that remote host able to reach resources in the Internet? Is that remote host able to reach resources in the remote office?

[Georg Pauwen]

Hello,

post the full running configuration of the 2851 router, maybe we can spot something. The 2851 is a rather ancient (end of sale 2011) device, so you are running at the very least an outdated IOS version...