Windows Firewall and ICS

[DWalker]

I upgraded my host computer from 2000 to XP, and I am having trouble
getting ICS to work now. The other computer is a laptop with a wireless
card, and my host computer has a LAN card that's cabled to the DSL
modem/router, and a wireless PCI card.

The two computers are in the same subnet (192.168.0.x) and in the same
workgroup, and when the host was Windows 2000, they were sharing
folders. After upgrading the host to XP, I had to install NetBEUI on
both machines (the laptop was XP already) in order to see the shared
folders. It's a peer-to-peer wireless network.

The problem is that while NetBeui is working and I can share folders and
the host's printer, Internet connectivity is not working. The laptop
computer can't get to any Web sites, and it also can't ping the host
computer's 192.168.0.1 address. (The ICMP echo setting is turned on in
the host's firewall.)

In the Windows firewall log on the host computer, I see DNS port 53
being blocked. I can add an exception to allow this port, but why isn't
this already set up? Am I supposed to have to add this port myself to
get ICS working with Windows firewall? Surely this has been thought of
and addressed already. (I found one Web page that suggested adding UDP
port 53 and TCP ports 53, 139, and 445 to the Windows Firewall
exceptions list on the host.) I can do this, but why isn't it built in?

Given that the Internet connection would occasionally quit before the
upgrade of the host to Windows XP, is it conceivable that the (fairly
old) wireless cards in the laptop and/or the host are going flaky? Can
they go bad in such a way that NetBEUI would work but TCP would not
work? That doesn't sound likely...

Thanks for any suggestions.

David Walker

 

[N. Miller]

I upgraded my host computer from 2000 to XP, and I am having trouble
getting ICS to work now. The other computer is a laptop with a wireless
card, and my host computer has a LAN card that's cabled to the DSL
modem/router, and a wireless PCI card.

The two computers are in the same subnet (192.168.0.x) and in the same
workgroup, and when the host was Windows 2000, they were sharing
folders. After upgrading the host to XP, I had to install NetBEUI on
both machines (the laptop was XP already) in order to see the shared
folders. It's a peer-to-peer wireless network.

The problem is that while NetBeui is working and I can share folders and
the host's printer, Internet connectivity is not working. The laptop
computer can't get to any Web sites, and it also can't ping the host
computer's 192.168.0.1 address. (The ICMP echo setting is turned on in
the host's firewall.)

In the Windows firewall log on the host computer, I see DNS port 53
being blocked. I can add an exception to allow this port, but why isn't
this already set up? Am I supposed to have to add this port myself to
get ICS working with Windows firewall? Surely this has been thought of
and addressed already. (I found one Web page that suggested adding UDP
port 53 and TCP ports 53, 139, and 445 to the Windows Firewall
exceptions list on the host.) I can do this, but why isn't it built in?

Given that the Internet connection would occasionally quit before the
upgrade of the host to Windows XP, is it conceivable that the (fairly
old) wireless cards in the laptop and/or the host are going flaky? Can
they go bad in such a way that NetBEUI would work but TCP would not
work? That doesn't sound likely...

What prompted you to install NetBEUI? I have never found it necessary.
Remove it. If you haven't already changed your modem to either a different
network address (one other than 192.168.0.0/24), or placed it in bridge
operating mode, do so. Reconfigure ICS, and let it handle DHCP. Let the
laptop obtain an IP address automatically. If you must use static IP
address assignment, learn how to tell the laptop where to find DNS service,
and the gateway.

I can't answer the Windows Firewall questions you are asking. I do know
that on both Windows XP computers where I enabled the Windows Firewall, I
did not have to take additional steps for the DNS exceptions; I can only
presume that WCF does do that automatically; unless something unusual is
going on.

It is not likely flaky hardware. More like some kind of TCP/IP conflict; as
if, perhaps, the modem is in the same network as the laptop. That is
trouble.