On my home network I have a Cisco Linksys Simultaneous Dual-N Band Wireless Router that has a built-in firewall, and I run McAfee Security Center that also includes a firewall for each machine it is installed on. I tried sharing files and folders, and printers, between a wired PC and a wireless PC, but was denied. It makes no difference on a network if the PCs are wired or wireless, because they all look the same on the network, and use the same protocols.
Since I could see the other PC on the network, but I could not see any printers, or shared files and folders, I suspected the McAfee firewall was blocking the ports needed to share.
Let’s setup sharing between these computers.

First click the Windows Start button -> Control Panel -> Network and Sharing Center -> Manage Network Connections, then right-click on the Local Area Connection or Wireless Area Connection -> Properties, and make sure the File and Printer Sharing for Microsoft Networks box is checked.

The settings under Windows Start button -> Control Panel -> Network and Sharing Center should look like the following for most home networks.

This article does not cover the Windows Firewall settings, but if you need to you go to Windows Firewall Settings -> Exceptions tab, and add both TCP/IP and UDP ports 137 to 139.
Open the McAfee Security Center. To open right-click the McAfee icon in the tray by the clock, then click Open SecurityCenter.
Using the Advanced Menu
Click Configure in the bottom left of the window, then click Internet and Network.

Using the Basic Menu
Under Common Tasks you should be on the Home menu.

Click Internet and Network then click Configure.

Under Firewall protection click the Advanced button.

Under Firewall click System Services.

Make sure Windows File Sharing (NETBIOS) Ports 137-139 is checked, select that option, then click Edit.

Under Edit System Service Rule type 137-139 into the Local UDP Ports field. Your settings should look like the ones in the screenshot below.

Now just click OK until the windows close, then close the remaining McAfee windows, and you should now be able to share printers, files and folders, with other PCs across your wired network and wireless network.
Note: You only need to open ports 137-139 on the PC that is sharing the printers, files, and folders.
Click here to learn how to share folders and printers over a network.
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