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ICS - Internet Connection Sharing not working

Anonymous
2010-07-04T10:24:11+00:00

I am building two computers with Win7 Ultimate and need to share a dialup connection over a wired network. I have gotten file sharing to work between the two machines, and followed all the instructions concerning ICS, but still can't get the non-host machine to connect to the Internet. I selected the option on the host machine to allow machines on the network to control the connection, and sure enough, when I plug in the crossover cord connecting the two, the host dials up. However no program on the non-host machine can actually communicate.

Windows for home | Previous Windows versions | Internet and connectivity

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  1. Anonymous
    2010-07-05T07:07:22+00:00

    You're in the right place.  The host's wired network connection IPv4 address isn't what it should be, indicating that ICS isn't set up properly. 

    While still in "Control Panel\Network and Internet\Network Connections", right-click the dial-up connection and click Properties >  Sharing .  If the Internet Connection Sharing box is checked, un-check it and click OK.  Then go back and put a check mark in that box to re-enable Internet Connection Sharing.  If a box appears asking you to select a private network connection, select the wired network connection from the menu.

    Boulder Computer Maven

    Microsoft Most Valuable Professional

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  1. Anonymous
    2010-07-04T20:15:13+00:00

    This should help you find the problem:

    1. On the host machine, double-click the Local Area Connection and click Details .  It should show:

       IPv4 Address: 192.168.137.1

       IPv4 Subnet Mask: 255.255.255.0

       IPv4 Default Gateway: none

       IPv4 DNS Server = none

    1. On the non-host machine, double-click the Local Area Connection and click Details .  It should show:

       IPv4 Address: 192.168.137.x (1<x<255)

       IP4v Subnet Mask: 255.255.255.0

       IPv4 Default Gateway: 192.168.137.1

       IPv4 DNS Server = 192.168.137.1

    1. If #1 and #2 are right, open a command prompt window on the non-host machine and enter these lines.  Each one should get four replies:

       ping 192.168.137.1

       ping 74.125.19.103

       ping google.com

    1. If #1-#3 are right, enter these addresses in Internet Explorer on the non-host machine.  They should both take you to the Google web page:

       http://74.125.19.103

       http://google.com

    Boulder Computer Maven

    Microsoft Most Valuable Professional

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  2. Anonymous
    2010-07-05T17:54:03+00:00

    You're welcome, Ron.  I'm glad that my suggestion helped you fix the problem.

    I think that VirtualBox is a great program.  I use it all the time, running Windows XP, Vista, and 7 virtual machines.  It creates a VirtualBox Host-Only Network connection.  I suspect that ICS was initially set up to use that for the private network connection.  That would explain why your client machine couldn't connect to the Internet and the host machine's wired network connection had an Autoconfiguration IPv4 Address.

    By design, ICS uses the 192.168.137.x address block.  I think that Microsoft chose that to avoid address conflicts with home broadband routers, which typically use 192.168.0.x, 192.168.1.x, or 192.168.2.x.

    Boulder Computer Maven

    Microsoft Most Valuable Professional

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  3. Anonymous
    2010-07-05T10:39:47+00:00

    Thanks for the help, that fixed the problem.

    I believe this happened because when I first enabled ICS, I had Oracle/Sun VM Virtualbox installed, part of which is a virtual NIC. It may have taken up the usual ICS address space forcing Windows to choose the other (I am speculating here). In the course of trying to make ICS work I removed Virtualbox, but ICS was still installed in the wrong block of addresses, by what you are telling me. Without the virutal NIC there, it defaulted to the correct value when I disabled and re-enabled it, as you suggested.

    It would be fascinating to know why ICS can only work in the 192.168.137.x address block, and if Virtualbox was the culprit. I will play with this if I have the time.

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  4. Anonymous
    2010-07-05T05:58:07+00:00

    I am not sure if I am in the right place. "1. On the host machine, double-click the Local Area Connection and click **Details"**does not say where to click. The closest I can come to this is "Control Panel\Network and Sharing Center\Change Adapter Settings," which brings up an explorer window with "Control Panel\Network and Internet\Network Connections" in the address bar. When I double click on the wired network connection and then click "Details" there, I get the "Network Connection Details" box which shows, not specifically the IPv4 address, but the "Autoconfiguration IPv4 Address" of 169.254.49.120, and the "IPv4 Subnet Mask" of 255.255.0.0.

    Now, this is another block of reserved addresses like 192,168.x.x. I do not know if this is the trouble, since theoretically a network can reside in either block just fine. Nor do I know how to change this, if it is indeed the problem. The client machine uses 169.254.177.66 as its address.

    Is this the problem, and, if so, how do I fix it? The two machines do network, can exchange files, and the client can control the modem and dial up. It just can't access the internet.

    Thanks.

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