How to Use Filter Wireshark Mac: A More Granular Approach

When working with Wireshark on your Mac, filtering traffic can be a crucial step in analyzing network activity. However, when it comes to filtering MAC addresses, the bitwise AND operator may not provide the level of granularity you need. This is because the operator is not designed to mask bits within the 4-bit nibble, leading to issues with matching certain characters.

For example, attempting to use a display filter like `wlan.da == 02:01:02:03:04:05` will result in a match for any MAC address that has the second character as either '2', '6', 'a', or 'e'. This is because the bitwise AND operator will be true when attempting to match these characters.

The issue arises from the fact that many device manufacturers randomize the MAC address during WLAN discovery and association. As a result, filtering MAC addresses can become more complex. To overcome this limitation, you may need to provide a mask that applies to bits within a nibble or compile a change to the 802.11 protocol dissector to apply to wlan.addr, wlan.ta, wlan.ra, wlan.da, and wlan.sa filters.

The problem is further compounded by the fact that many MAC addresses follow RFC 7042 (section 2.1) rules, where the second least significant bit of the 48-bit MAC address's most significant byte is set, signifying that it is locally administered. This makes it even more essential to have a more granular way to filter MAC addresses.

To achieve this level of granularity, you can consider using a different approach, such as applying a mask that targets specific bits within a nibble. Alternatively, you could modify the 802.11 protocol dissector to provide a more detailed filtering mechanism for wlan.addr, wlan.ta, wlan.ra, wlan.da, and wlan.sa filters.

By taking these steps, you can gain a better understanding of your network traffic and make more informed decisions about how to filter and analyze MAC addresses using Wireshark on your Mac.

How to use filter wireshark mac