Small Network Troubleshooting Guide

One of most frequent questions we are asked revolves around home or small office networks, usually along the following lines...

"I've just been out and brought a couple of network cards and a cable and joined my PC's together but can't seem to get them to talk to each other..." or "..we've had these PC's networked for years but never been able to share files..."

I guess if you're reading this then you're probably one of them! OK, so where to we start? Well there are whole books dedicated to networking so we're not going to be able to cover it all!

Most problems originate with software settings but before we go there we'll start with basic checks to save time later.

Ensure the hardware is properly fitted inside the PC - follow instructions carefully if installing yourself, with the PC switched OFF! NEVER leave any screws or other metal objects on top of power supplies etc where the may drop into the case - this can be expensive! Don't force a card which won't fit, try another slot - many cheap PC's are of a poor quality and cards don't align very well. A good tip when installing any PCI card into a PC is to switch the PC OFF at the main socket but leave the lead plugged in this keeps the unit earthed but removes power. It is not sufficient to just shut down a PC and rely on the 'soft-power-off' feature as most ATX PC's have a wake-on-LAN or wake-on-RING feature and it isn't uncommon for them to switch on when plugging in a card!!!

Once installed and powered up, load any device drivers required for your operating system and check in the device manager to ensure that there are no red crosses or yellow exclaimation marks. If there are any driver problems for your network card they should show up here.

Check the cable between the machines - if you are connected via a hub or switch you will need to use a 'straight' CAT5 cable but if you are connecting directly to another device or computer the you will need a 'cross-over' CAT5 cable. If you are using the old co-axial (TV arial type) then you must have a 'T' connector at each 'node' (connection) and a terminator at either end of the cable: thus the cable runs to and from each PC.

In the network settings (right-click network neighbourhood and choose properties) you require an entry of type 'protocol' for TCP/IP. Once added you will probably see more than one entry. Select the one for your network card and click 'properties'. You should now ensure that both IP addresses (one on each machine) are unique but in the same range e.g. 192.168.1.1 and 192.168.1.2 and that both subnet masks are the same, e.g. 255.255.255.0. Unless your computer is on a large network, the subnet will usually be 255.255.255.0 - more information on subnet ranges can be found on the web for those interested. We'll add some more articles in due course. If you have an Ethernet router on your network for internet connectivity it will often use 192.168.1.1 or 192.168.0.1 - these are recommended address ranges for small private networks. Ideally you should start your address ranges from x.x.x.10 and note that that the maximums are 254. If you do have a server or router on your network, they could have a DHCP service running which will automatically give your PC an IP address, subnet mask and gateway. To find out, set the IP address to automatic and run IPCONFIG from a command prompt (or WINIPCFG for Windows 95/98/ME) - Look for the address applicable to the network card not a dial-up. It shouldn't be 0.0.0.0 but could be almost any other number. Check the GATEWAY address and if this is in the same range (with a subnet of 255.255.255.0) you're probably getting a locally issued address. If you are on a small network with no router or server, you will probably need to set the IP addresses manually.

The next stage is to check for connectivity, you should be able to 'talk' at TCP/IP level to the other devices on the network. A useful utility for this is 'PING' - at a command prompt, type PING x.x.x.x (where x.x.x.x is the address of the other machine or router) - you should get 4 replies with 0% loss. If you have a router connected to the web, you should be able to ping almost any computer on the web (some block ping replies however...) our server here is 212.69.197.168 - feel free to use it to test.

If you want to be able to browse shared folders on other machines you should also ensure that the workgroup name is set the same and ensure that file and printer sharing for windows networks is installed and enabled on both machines. Shared folders should, ideally be limited to local users or if on a domain, 'authenticated users' but in practice we encounter many networks with folders shared to 'everyone' and if you are having trouble sharing that's a good place to start! If you still cannot 'see' folders or files on the other machines, check that there are no personal firewalls running on either machine - if there are, temporarily close them to identify the problem. If the firewall is stopping the share, check with the help file or user guide for your particular firewall for how to allow some computers to access files through the firewall, configure this and reinstate the firewall. Finally, if you intend to use internet connection sharing, the gateway of the second machine should be set to the IP address of the one with the Intenet connection - thus traffic will be 'routed' through the card on the second machine which will in turn pass this through its modem or other Internet connection. There is an ICS wizard with Windows XP that will help you with this or call us for detail instructions.

If your computer is on a network with an Internet connection but you cannot connect or open web pages, follow the basic steps above to check hardware and TCP/IP are working and try pinging a web address (e.g. 'ping www.rccds.co.uk') if this fails but you can ping the IP 212.69.197.168 you have a DNS problem - DNS is usually automatic but try adding the IP address of your router into the first DNS server box or ask your ISP for it's DNS servers. If you can ping but not browse web servers, check firewall settings and scan for viruses. If there are only some sites you cannot browse, also check the 'hosts' file in Windows - particularly if you've recently had virus trouble. If you cannot ping any sites either, you will need to check your gateway address and router - your PC's gateway should be the address of the router - try pinging. If you can ping the router but not beyond, the router is either disconnected from the web (Logged out etc), misconfigured or faulty. Most Routers have a web-based configuration utility - try pointing your browser to the IP address of the router (e.g. enter http://192.168.1.1 in the address bar and press enter - you will probably require a login name and password check userguide or manual for defaults if you don't know it or reset the router to factory config if it's lost. (Ensure that you know your ISP login details if you need to do this as it will wipe ALL configuration data!)

If you've got to here and still can't resolve the issue then you've probably tried all you can and some technical help maybe required - please feel free to email us or call!