Wireshark-dev: Re: [Wireshark-dev] Unable to set data link type (EN10MB is not one of the DLTs
From: Guy Harris <[email protected]>
Date: Wed, 16 Jan 2008 02:24:34 -0800
Stig Bjørlykke wrote:

$ sudo tcpdump -i wlt1
tcpdump: WARNING: wlt1: no IPv4 address assigned
tcpdump: unsupported data link type IEEE802_11_RADIO_AVS
Sigh.  Yeah, I discovered that tcpdump didn't support AVS recently 
(testing it on a Mac mini running Leopard).  I checked a fix into the 
main and 1.0 tcpdump branches.
What happens if you do

	sudo tcpdump -i wlt1 -w /dev/null

(in that case, it doesn't need to understand the link-layer type, as it just writes out the raw packets without dissecting them)?
$ tcpdump -V
tcpdump version 3.9.8
libpcap version 0.9.5

But I'm sure I have captured wireless on this computer with AVS headers before.
Before, or after, upgrading to 10.4.11?

Perhaps the driver was using DLT_PRISM_HEADER (which can also be used for AVS headers), or perhaps it was using radiotap rather than AVS headers.