Multiple IP adressess

If your ISP offers the option of purchasing multiple IP addresses (CablemodemHelp.com lists some that do), you may want to consider this as the way to connect multiple computers to one cable modem.

To help you decide, here are the Pros and Cons of this method.

Be sure to go to the "Configure Client" page to setup your client computers.

The wiring setup is very simple as shown in the diagram below.





If you compare the diagram above to the diagram below, you should note the following differences:

There is no longer a "Sharing" computer, so each computer's Internet access is independent of the other's.
There is only one NIC per computer.
Both the cable modem and the computers are plugged into the hub, so there is not a separate LAN created that keeps your local network traffic off the ISP's network.




All wiring is done with UTP cable (normal 10baseT cable), with the possible exception of the cable that connects the cable modem to the hub.

If your hub has an "expansion" or "uplink" port, then you can use a normal UTP cable. If your hub does not have this capability, or if the green "Link" light on the cable modem and the hub port that the cable modem is plugged into do not light up when have the cable plugged in at both ends, you will need to use a "crossover" cable. (Note for some hubs you may have to set a switch to convert a port to "uplink" mode.) See this page for more information on crossover cables.




Having trouble with Multiple purchased IP addresses?
I get many emails from people who have purchased additional IP addresses from their cable ISP and who can't get both computers to properly share the connection. A common problem is that only one computer will connect at a time.
In other cases, they get a proper Internet connection, but can't get File and Printer sharing to work.

Many people assume that they are doing something wrong when they can't get this option to work properly, but sometimes the fault lies with the cable ISP!

Helpful reader Adrian Neilson couldn't get the second IP address that he purchased to work. It took multiple calls to his cable ISP, and escalation to a service manager, but the problem was found to be the Flash ROM on his cable modem wasn't changed to allow more than one IP address to connect.

If you choose the multiple option, you are paying for a product/service, and your ISP is obligated to install it or help you install it. You may need to be persistent and escalate the problem to the second or third level or tech support.

If they will not provide assistance (or are unable to get it working), cancel the service!

What they can refuse to do is help you with any File or Printer sharing problems, since they are in most cases selling you only shared Internet access.


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If you are having trouble getting File and Printer sharing to work and have multiple IP addresses from your ISP:
In some cases, the second IP address that they provide to you will look different than the first one.
(Example: 172.24.33.45 and 172.24.29.2).

In the example above, the two addresses are in a "Class B" subnet, so a "normal" "Class C" TCP/IP subnet mask setting of 255.255.255.0 won't work.
(If you'd like to learn more about IP Addressing and what "Classes" are, 3com's 1996 whitepaper called "Understanding IP Addressing" -- in PDF format -- will tell you more than you probably want to know!)

The easiest way to fix this is to add the NetBeui or IPX/SPX protocol (make sure you enable NetBIOS over IPX/SPX) to all your computers and make sure it is bound to Client for Microsoft Networks and File and Printer Sharing for Microsoft Networks. This will set up File and Printer sharing independently from TCP/IP, so it won't matter what the TCP/IP settings are! Make sure you unbind these from TCP/IP.

You can also try using a Class B subnet mask if your ISP gave you one along with the IP addresses (it will be something other than 255.255.255.0) Make sure you do this on all computers that are connected into the hub. Depending on your ISP's DNS and gateway server IP addresses, however, this might not work.

network troubleshooting in windows

Windows XP Network Troubleshooting


Troubleshooting TCP/IP - Detailed Steps
This article shows how to troubleshoot TCP/IP connectivity between computers on a Windows network. If you haven’t already done so, disable XP’s Internet Connection Firewall on all local area network connections, and remove all firewall programs on the network. Improperly configured firewalls are the most common cause of TCP/IP problems.

Open a Command Prompt Window
For many of these steps, you’ll be typing at the command prompt. To open a command prompt window in Windows 2000 or XP, click Start | Run, type cmd in the box, and click OK. To open a command prompt window in Windows 95, 98, or Me, click Start | Run, type command in the box, and click OK. Type one command per line, and press Enter after each one to execute it. To close the command prompt window, use the exit command.

Determine the TCP/IP Settings


Determine the TCP/IP settings of each computer on the local area network. In XP, open the Network Connections folder, right click the LAN connection, and click Status | Support | Details. For example, here are the Status and Details views for the LAN connection on an Internet Connection Sharing host.




In Windows 95/98/Me, click Start | Run, type winipcfg in the box, and click OK. Select the LAN adapter from the menu, and click More Info. Here’s the winipcfg view for an ICS client running Windows Me.



You can also see the TCP/IP settings from the command prompt. This is especially convenient if a computer has more than one network adapter. Use the ipconfig /all command, which is available in all versions except Windows 95. The output from this command can be long, so it’s best to write it to a file. Specify the file name in the command this way:

ipconfig /all >ipconfig.txt

Here’s the output for a Windows XP ICS host that’s sharing its cable modem connection:



Description of TCP/IP Settings
Here are the TCP/IP settings that are used in network troubleshooting:

IP Address – Unique address assigned to a network adapter. A computer with multiple network adapters has an IP address for each one, and each one must be in a different subnet.
Subnet Mask – Used in conjunction with the IP address to determine which subnet an adapter belongs to. At the simplest level, communication is only possible between two network adapters when they’re in the same subnet.
Default Gateway - IP address of a computer or router, on one of this computer’s local area networks, that knows how to communicate with subnets not present on this computer. For an Internet connection, the default gateway is a router belonging to your Internet service provider, and all access to sites on the Internet goes through it. For an ICS client, the default gateway is the ICS host. If you use a hardware router, it serves as the default gateway.
DHCP Server – If an adapter is configured to obtain an IP address automatically, this is the address of the server that provides it. It could be your ISP, an ICS host, or a hardware router.
DNS Servers – IP address of one or more Domain Name Server computers. DNS servers translate Internet names (like www.xyz.com) to their IP addresses (like 63.146.109.111).
Subnets
See our article on subnets for a brief description of how they work. For more details, see this Microsoft Knowledge Base article.

If two computers are supposed to be on the same subnet, but aren’t, something is wrong with the network hardware or software configuration. This is most likely to happen when one of them receives an IP address of 169.254.x.x, which indicates that:

It’s configured to obtain an IP address automatically.
It couldn’t find a DHPC server on the network to make the assignment.
Windows assigned it an Automatic Private IP Address.
See our article on Specific Networking Problems and Their Solutions for more information.

Pinging


The ping command is the basic tool for testing TCP/IP connectivity. It sends a special packet (called ICMP Echo) to a particular IP address and looks for a reply. If everything is working right, the reply comes back. If not, the ping times out in a few seconds. By default, the ping command repeats the process four times. Here’s an example of an ICS client computer pinging a Windows XP Home Edition ICS host, using the host’s IP address and its computer name.

When ping fails, you’ll see one of these error messages:

Request timed out - The IP address is valid, but there’s no reply from it. If the IP address is on a local area network, the most likely cause is a firewall program blocking the ping.
Unknown host or Ping request could not find host - The computer name doesn’t exist on the local area network. Make sure that NetBIOS over TCP/IP is enabled.
Destination host unreachable – The IP address isn’t on a local area network, and the default gateway can’t access it. Either there’s no default gateway, its address is wrong, or it isn’t functioning.
Pinging the Local Area Network
Here is a series of ping commands to use in finding where a problem occurs on a local area network. Run them in the order shown, and don’t go on to the next command until all of the previous commands work properly. In this example:

The computer being tested is named Winxp, with IP address 192.168.1.101.
There’s another computer on the network, named Win98, with IP address 192.168.1.123
Substitute the appropriate IP addresses and computer names for your network.

Command
Target
What Ping Failure Indicates

ping 127.0.0.1
Loopback address
Corrupted TCP/IP installation

ping localhost
Loopback name
Corrupted TCP/IP installation

ping 192.168.1.101
This computer’s IP address
Corrupted TCP/IP installation

ping winxp
This computer’s name
Corrupted TCP/IP installation

ping 192.168.1.123
Another computer’s IP address
Bad hardware or NIC driver

ping win98
Another computer’s name
NetBIOS name resolution failure


To fix a corrupted TCP/IP Installation on Windows XP, follow the steps in this Microsoft Knowledge Base article. For Windows 95/98/Me, un-install the TCP/IP protocol in Control Panel | Network, reboot, and re-install it. If that doesn’t fix it, use this procedure on Windows 95 or 98.

Pinging the Internet
You can also use ping to find a problem with Internet access. Run these commands in the order shown, and don’t go on to the next command until all of the previous commands work properly. Use the Default Gateway and DNS Server addresses that you got from the winipcfg or ipconfig /all command.

Command
Target
What Ping Failure Indicates

ping w.x.y.z
Default Gateway
Default Gateway down

ping w.x.y.z
DNS Server
DNS Server down

ping w.x.y.z
Web site IP address
Internet service provider or web site down

ping www.something.com
Web site name
DNS Server down or web site down

i have installed symantec antivirus. whenever my computer opens it show message " can't find script to the file virusremoval.vbs"

i have installed symantec antivirus. whenever my computer opens it show message " can't find script to the file virusremoval.vbs"
how to remove it?


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That is a worm virus find the folder where it is residing then use the
cmd (DOS) terminal to navigate to that folder where the file resides.

In the command prompt, change the file's attribute by typing:
attrib -h -r -s virusremoval.vbs
then delete the file by typing
del virusremoval.vbs
Perform this steps it may resolve the issue.