Can the remote site users access other systems on the main site network, that is, systems on the same subnet as the Unix server? Or do they just have a problem with the Unix server? If they can access other systems on the same subnet as Unix server, then Unix server is the problem (see suggestion 3 below).
Can remote site users get out to the Internet (WWW)?
I am not sure I understand your network design completely, but from what I read in your post here is what I would suggest:
1. Check the L3 switch at main hub site: specifically, look for an ip route that matches the subnet used at the remote site for users.
2. If the route is missing, then it is not being learned by EIGRP or OSPF. You can either put in static routes to the remote subnet, or on the remote site L3/router you can enable the routing protocols on that subnet's interface. (You probably do not have the user subnet listed under "router ospf ...." on the remote L3 device, so it is not being advertised on other subnets and learned by the L3 devices at the main site.)
3. Depending on how your network is set up, you may also need to tell the Unix server how to reach the remote subnet. It may be receiving traffic from the inside, and sending replies out to the Internet instead of back to an internal router.
I would need to know more details about your network, in order to give you more specific things to check. But this should get you started.
Hope this helps.
