Technical Tip: Channels supported by the WiFi user

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Description	This article describes the channel support of 5 GHz clients.
Scope	FortiAP.
Solution	Not all Wireless clients that support the 5 GHz band support all channels. Some users may be unable to hear some channels, especially DFS channels. To determine which channels my client supports, capturing an association request packet is recommended, as clients usually advertise their capabilities in this packet. The example below shows a capture of the association request packet: announced in the IEEE 802.11 Wireless Management, Tagged parameters, and supported channels section. Use this wireshark filter to display only association request frames. wlan.fc.type_subtype eq 0 As shown, this client does not support any DFS channel, so it will be important to disable them from the channel plan. See Technical Tip: How to capture packets over the air (OTA) for wireless troubleshooting for a demonstration of how to perform a packet capture on the air. Other ways to way to find this information include consulting the FCC page, trying to find the chipset that the wireless card has, or viewing Mike Albano's list.