Getting Invalid MAC Address Error Message

For the past week, I have been noticing slower Internet speed on my home computers without any reasons. I am not using any torrents or other bandwidth consuming tools on any of the PCs but recently one representative from my ISP informed me about over bandwidth usage. I inquired her about my reduced bandwidth but she said everything from their side was working perfectly. Since the ISP side is working perfectly, the problem must be from our end. Perhaps some other user is using our wireless anonymously to access the Internet and may be downloading large files. Airtel is my Internet Service Provider and my experience with them is so far good. I have been getting almost the same speed they offered and it is the time to instigate the culprit who uses my home WiFi. Airtel supplied D-Link DSL 2730U modem and it doesn't have any feature to find the log of connected devices. So I have decided to change the current WiFi password and allow only my home computers and laptop to join the WiFi by using MAC Restriction. However, soon I have noticed a new error message while adding MAC addresses to the allowed devices list. MAC address "XX:XX:XX:XX:XX:XX" is invalid MAC address is the error message which prevented me from adding.

Prevent Automatic PC Reboot
The error message looks like the one below.


If you don't know how to improve the WiFi security on D-Link DSL 2730U, visit the link below.
How to Secure Airtel DSL Modem

This article discusses the common reasons for rejecting a Physical number by a router while configuring a Media Access Control filter.

• If you are using a different format to enter Media Access Control number other than the one which is supported by the device, you will receive the invalid MAC alert. Once you click on the OK button, the entries you entered will be deleted automatically. So the first step you have to do, if you are facing this situation, is to check the correct format which is supported by the device. Certain devices use ":" to separate the HEXA decimals but some devices use "-". Try different format and use the one which is approved. I have used a hyphen instead of a colon to separate the numbers because my computer showed the MAC number in xx-xx-xx-xx-xx-xx format. A simple mistake but D-link rejected my entries.
  
  
• Another solution for this issue is to upgrade the current firmware. If your router is having an outdated version of firmware, it is the time to flash it with latest one.

I have changed the format from hyphen to colon. After that change, D-Link showed no error.

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