I used Ipconfig/all to find the MAC ADDRESS for my new DELL Studio 14z Notebook computer, and feed the MAC address to the D-LINK router that use MAC FILTER as security. The D-Link router complained that the MAC ADDRESS was invalid. Why? I have to switch off the MAC FILTER security for now.

Make sure that you entered only 12 digits. The value of each digit is HEX so only 0-F values are allowed. To clarify these are the values (do not mistake zero for O). 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. You may need to follow a certain format when typing in the values either XX-XX-XX-XX-XX-XX or XXXXXXXXXXXX. Visit: anITKB.com, an IT Knowledge Base.

With this new Notebook just arrived, I have 4 Dell Notebook computers at home, and this is the only one giving me trouble. I double checked the 6 pairs of double hexa-digit MAC address with my son (younger and better vision than me), removed, and re-entered. Still, if I include this new MAC address, D-LINK complainted about invalid MAC address, and if I remove it, D-Link is ok with the rest of 3 Notebook. I did feel strange that the MAC address for this new Notebook starts with 74 (I think, but not 00 for sure. I am at office now), while the ohter 3 Notebook start with 00. Is there any known issue that ipconfig/all might be reporting "wrong" or "different" MAC address than what D-Link is reading for Windows 7 OS?

None that I know of. However, when you are attempting to enter the MAC into the D-Link management application, there is no checking to see if that MAC actually belongs to a computer, so the focus should remain on why the D-Link does not allow for that MAC to be entered. If you have access to another router, it would be interesting if you can enter the same MAC and see if its accepted. If not, I would shift the focus to the MAC you are entering. If another router accepts it, then the focus should remain on the D-Link router. Maybe the router has a bug and needs a firmware update. Have you checked to see if D-Link has posted any firmware updates? Visit: anITKB.com, an IT Knowledge Base.

Hi, Jorge’s suggestion is worth to perform and we can narrow down the cause. Also, I suggest you open Device Manager and assure the Mac address is not modified. 1. Type DEVMGMT.MSC in Search box in Start menu, right click it and select “Run as administrator” option. 2. Navigate to the network adapter and right click it, and then select Properties. 3. Switch to Advanced tab and click “Network address” option. 4. Assure that the “Not Present” option is selected. If the issue persists, please also upgrade the NIC driver to the latest one for a test. Thanks, Novak