When you need to troubleshoot problems connecting your 4D Client and 4D Server over a network, it's helpful to think of the networking setup as a series of layers. At the lowest level, you have the hardware: the network cards in your computer, the cabling, and any routers or other network devices. Above that you have the networking at the operating system level. And on top of those layers you have 4D's networking.

In order for 4D's networking to work, the networking at the underlying levels needs to be functioning properly. If you're having problems connecting your 4D Client and 4D Server, the first thing you want to determine is that the underlying network is working properly.

If you are using the TCP/IP network protocol, a quick and easy way to test the network at the operating system level is by "pinging" one machine from another. This sends a series of TCP packets across the network from one machine to the other, then waits to receive replies back. If there are problems, you either won't get any replies back, or the replies take a very long time to come back.

On the Windows platform, the operating system's Start menu includes a convenient PING command that you can use from the MS-DOS Command Prompt. You type in the command "PING" followed by a space and the TCP/IP address of a machine, and press Enter. The screen then displays the information about how long the replies took to come back.

Unfortunately, the Macintosh operating system does not come with this kind of handy utility built-in. To get around this, you'd typically download a separate ping utility, such as "MacTCP Ping" from Apple Computer. But if you were at a site that was having network problems and hadn't remembered to bring along a copy of this utility, downloading might not be an option.

Now 4D v6.5 includes a handy NET_Ping command. This comes with the new <4D Internet Commands plug-in included with 4D v6.5. You can ping any machine with an IP address that is accessible via your network. You can specify either the IP address or the host name. The command will enable you to determine if the pinged machine is currently active.