Achilles Tziatzios wrote:
Hi, I would like to know if it is possible with Ethereal to capture
information concerning the MAC layer retransmissions of packets as well
as packet headers information in the MAC layer, for a wireless IEEE
802.11b network.
If you want to capture packets with 802.11 headers, rather than fake
Ethernet headers, you'll need to be running on sufficiently recent
versions of Linux or of one of the free-software BSDs; see the page
whose URL Ulf Lamping provided. Capturing 802.11 headers on other
operating systems, such as Windows or Mac OS X, is *not* supported, as
those OSes don't offer any mechanism to allow libpcap/WinPcap to capture
them.
If you want to see 802.11 retransmissions, you might have to do a
"third-party" promiscuous or monitor-mode capture; you probably won't
see them if you're capturing on the machine doing the retransmissions
(at least not if they're being done by the 802.11 adapter, as capturing
of outgoing traffic is done at the software level before packets are
supplied to the adapter) or the machine to which the retransmissions are
being done (at least not if the 802.11 adapter recognizes them and
ignores them, or if the reason retransmissions are being done is that
the receiving machine didn't receive and acknowledge the original
transmission).
At least on Linux, you'll probably have to capture in monitor mode
*anyway* in order to see 802.11 headers.