win 7 laptop can't connect to xp desktop via wifi

[nite_monkey]

I've got a kind of weird problem here. My mom has a toshiba laptop running windows 7 home premium x86. It is connected to the internet via wifi, and works perfectly. The laptop can see and connect to my desktop computer which is running win7 pro x64, but it cannot connect to another computer on the network running windows xp pro x86 by typing it's name. The laptop can however connect to the xp computer if it types in the ip address of the xp computer. I figured the problem might have been a problem with the onboard wifi card, so we plugged in an external wifi card with the same results. Here is where it gets interesting. I turned off the wifi card on the laptop, and plugged an ethernet cable into the laptop, and it can now connect to the xp computer by typing in it's name instead of the ip address. So my question here is what would be causing the laptop to be doing this?

[40hz]

Is the workgroup name on the XP machine the same as it is on the two Win7 machines?

Oops. Cancel that. Was thinking of something else. 

[nite_monkey]

Is the workgroup name on the XP machine the same as it is on the two Win7 machines?

yes

[40hz]

Are you broadcasting the SSID on your WAP?

And what are you using for your firewall?

[Carol Haynes]

Does XP have proper sharing or simple sharing enabled? Look in Control Panel / Folder Options / View  it is the last item - untick it.

You then need to set up the sharing of folders manually on XP. I find this far less flaky than simple sharing which can be a bit hit and miss (even worse sharing with Vista). A vaild user on XP is "Everyone" so if it is a home network and you aren't sharing confidential info (!!) set the sharing permission for Everyone to Full control and it should pop up for all network users without any user profile restrictions.

Are you sure the workgroup names are the same? The default on all versions of Windows is "Workgroup" except for XP when, for some reason, MS changed it to "MSHOME".

Also try turning off your firewall on the laptop and other computers briefly and see if it works - if it does there is your problem.

[40hz]

Regarding firewall:

If it turns out to be the firewall, you'll need to unblock the following ports for discovery and f&p sharing with pre-Vista machines:

UDP 137
UDP 138
TCP 139

re: SSID blocking

Blocking the WAP from transmitting your SSID doesn't really provide much in the way of real security. And it has the unfortunate effect of sometimes causing odd and sporadic problems for wireless networking when running Windows XP.

If you've shut SSID broadcasting off on your router, turn it back on.  

[Shades]

If the problem still persists change the following in the Windows 7 PC:
In the advanced settings you can change the encryption. By default the Windows 7 PC uses the new and shiny 128-bits format to encrypt traffic. Windows XP networks use 40-bits/56-bits encryption.

This means that both computers can talk to each other but there is not much communication going on...unless you change the setting in the Windows 7 PC. I did that here in my network and the method really works.

And while you are at it...please kill the Homegroup services. Not only does networking revert back to the XP way of doing things, it actually becomes noticeably faster (between 10-15%).

Homegroup networking functionality only plays nice when you have a Windows 7 only network. And if you are slightly knowledgeable regarding Windows networking, do yourself a favor and disable it. NOW!

It is a miserable mess that Microsoft created...

[nite_monkey]

I don't have access to my wap (I don't have the admin password, my brother is the only one who knows it), but it isn't blocking ssid broadcasting.

The xp computer is using simple sharing (I might have to change it though, and see what that does)

I'm positive all of the computers are on the same workgroup (we use home instead of workgroup or mshome)

I tried disabling the firewall on the laptop (forgot to check the xp computer, I'll have to check it when I change simple sharing)

I'm not positive, but I believe I tried changing the 128-bits encryption option, and I believe it didn't do anything.

Though I'm not really sure if the simple sharing will do much though, because my desktop can connect to the xp computer, and the laptop can also connect to the xp computer if I disable wifi and connect via ethernet. (which doesn't make much sense to me...)

[Carol Haynes]

If it is purely a Wifi issue I'd guess it is a firewall problem as they often treat each interface separately.

[Stoic Joker]

The laptop can see and connect to my desktop computer which is running win7 pro x64, but it cannot connect to another computer on the network running windows xp pro x86 by typing it's name. The laptop can however connect to the xp computer if it types in the ip address of the xp computer.

If it can connect by IP, it can connect. So fiddling with SSIDs, sharing permissions, & etc. is probably just a good way to break something else.

Ping the IP, I'm guessing you can.

Ping the Name, I'm guessing you can't

Make sure that NetBIOS name resolution is enabled on all the relevent adapters, because this is a NetBIOS name resolution issue.

It could be a fight over who is the Browse Master, or it might just not be anouncing itself correctly. This is a big part of why I hate working on WorkGroup networks; XP is prone to pull this crap, and I never did find a clear cut method of troubleshooting it.

[nite_monkey]

I just got done checking the netbios settings, and netbios name resolution is enabled on all the computers.

[Carol Haynes]

Have your tried simply disabling all the firewalls? Seems the most likely problem.

[patthecat]

Most likely it is the DNS name resolution on the wireless router.  On my brother's wireless router, if I change the DNS server from the default of "obtain DNS server address automatically" (which means use the ISP's DNS server) to the DNS servers of OpenDNS, I am not able to refer to a network printer by name but I am successful in connecting to it by IP address.

If you cannot access your wireless router, then try on the machines in question to temporarily switch the DNS server address on the wireless card to point not to the router address (like 192.168.0.1, 192.168.1.1, 192.168.2.1, etc) but to your ISPs DNS server addresses.

[Carol Haynes]

Why should using the ISPs DNS make any difference to a local network setup?

[Stoic Joker]

Why should using the ISPs DNS make any difference to a local network setup?

I'd be curious about that also, given that the Windows default H node name resolution depends on (NetBIOS) broadcast first and only then looks to DNS. And as you said neither the ISP nor Open DNS will have DNS (Domain Naming System) info for a (workgroup) nonexistent internal domain.

However in patthecat's defense, network printers in a workgroup are notoriously bad at name resolution and can frequently require several restarts before remembering to announce themselves on the wire so they can be found.

[Stoic Joker]

I tried to find something on NetBIOS that was informative and concise...but this was the best I could do:
How NetBIOS Name Resolution Really Works

The WINS stuff won't apply but the rest may be helpful in narrowing down the culprit.

Before you have to dig through all that, are any of your machine names longer that 15 characters? If they are that can cause NetBIOS name resolution to fail.

[Deozaan]

Is it your hosts file?