Why is the windows firewall blocking my file sharing?

I used the standard trick of assigning permissions to the "Everyone" group to allow file sharing among all the Windows 7 and winXP computers on my home network. All was working fine until my son took his computer to school and they made him load their security software. When he came home for the summer, his computer could still see the network and file shares, but none of the other computers could see his shared files. This persisted even after I uninstalled the anti-virus software they made him install. I can fix the problem by disabling the windows firewall on his computer. That is probably safe here because of the firewall in my router, but I'm worried that might not be safe when he connects to other networks. Plus I can leave the windows firewall enabled on all my other computers, so I suspect there should be a better way around this problem. If I click "Diagnose" when my computer can't access my son's computer I get a message that says that windows can't find IPC$. So on my son's computer I opened a dos window and typed "net share ipc$" (a command I found from a google search about this problem). The response to this command was "System error 5 has occured; Access Denied". I don't know what to do at this point. Does anyone have any suggestions?

Thanks.
~Paul

Can we assume your son's computer is running Windows 7?

Have you check the workgroup to make sure it is the same as your network and checked the network on his system to make sure it shows as Private and not Public?

Originally Posted by Saltgrass

Can we assume your son's computer is running Windows 7?

Have you check the workgroup to make sure it is the same as your network and checked the network on his system to make sure it shows as Private and not Public?

Yes, correct assumption about the OS ... it is win7Pro x64.

Yes, I checked the workgroup and it is the same workgroup used by all the computers in my network. Also it is listed on my son's computer has a "Home Network" (i.e. not public).

So looks like the problem must be elsewhere. Any more ideas?

Thanks
~Paul

The only other thing I could suggest is to check the Advanced Sharing options on his system. Maybe one of them have been changed.

You might try looking through the Windows Firewall Inbound and Outbound rules to see if anything looks different for his system from your others.

Originally Posted by Saltgrass

The only other thing I could suggest is to check the Advanced Sharing options on his system. Maybe one of them have been changed.

You might try looking through the Windows Firewall Inbound and Outbound rules to see if anything looks different for his system from your others.

Oh my gosh ... you are right. In advanced sharing options, I expected file sharing to be on as I had once set it, but actually I found that it was turned off. How embarrassing that I could miss something so simple. My only excuse is that when I turned off the windows firewall I could see my son's disks on the network, so I assumed file sharing was set up properly. That is quite strange, although now that it is working I have little motivation to investigate. Thanks for your help!

~Paul

Well, I for one, have never made assumptions based on prior certainties..

Glad you got it working.