RPC Troubleshooting

The 4POS SC program uses Microsoft RPC calls (Remote procedure calls) to communicate with 4POS clients. The only configuration normally required is on the client (Utilities, Server) of the name of the computer on which the 4POS SC server is installed (also note the 'IMPORTANT' section below regarding remote access configuration on the server).
Note that the standard 4POS Retail does not support clients, please see the free 4Web utility if you just need other computers on the same network or internet to check inventory.

Requirements and Connectivity
The 4POS SC server requires Windows XP Professional or later. It is not able to provide the server service on 'Home' versions (they only support local procedure calls not RPCs. A server and client will work if installed on the same such computer).

Temporarily disable any firewalls on the server and client
Check the server name is correct (Windows control panel, System, case sensitive) and that the Windows workgroup is the same on both computers.
Ping by name to check connectivity and name resolution (Start, Run, CMD, 'ping servername') (see also tracert)
Ensure the Power options do not allow the server computer to sleep.
Check a router is not blocking the RPC ports (445 TCP and UDP)
IMPORTANT: Windows XP service pack 2 or later disables all remote access to a computer by default (including RPC calls). The computer on which the 4POS SC server is installed MUST have file and printer sharing enabled in order to accept incoming client requests.

Windows XP: In Windows Explorer, right click Local drive (C:), left click Properties then select Sharing. On the lower Network sharing and security box select:
If you understand the security risks but want to share files without running the wizard click here. Then click: Just enable file sharing.
Note it it NOT required that any files are then actually shared.

Windows 7, 8: In the Network and sharing center (Control panel, Network and sharing center) click Change advanced sharing settings. Turn on File and printer sharing and turn off Password protected sharing.

Services
The server program requires the Windows RPC service. It is normally started by default.

On the 4POS SC server program check that the service is active (Utilities, Server service checked)
On the server computer check the RPC service is running (Start, Run, CMD, 'Net start' and the list should include 'Remote Procedure Call (RPC)')
On the server computer check the RPC port 445 is monitored (Start, Run, CMD, 'netstat -ano').
In services (Administrative tools, Services) the settings should be:
RPC Service Started Automatic
RPC Locator service Stopped Manual
The components required on the network connection (Control panel, Local area connection, Properties) are the default which are Client for Microsoft networks, File and Printer sharing for Microsoft networks and Internet protocol.
The settings for the Internet protocol (Properties, Advanced, WINS) are NetBIOS setting, Default.

Further details
http://technet.microsoft.com/en-us/magazine/2007.07.howitworks.aspx
http://support.microsoft.com/kb/q177446/