Can't ping firewall

["Paul D. Robertson" <paul () compuwar net>]

I came across this in the last few days, and figured it's worth sharing.

One of my clients has a SonicWall firewall.  They were working on a
WindowsXP laptop, and could ping internal hosts, but not the firewall
(which has since been upgraded, so I'm not sure if the same problem exists
in the current codebase.)

It turns out the SonicWall was ignoring the ARP requests from the laptop.
A couple of minutes with a sniffer, and I'd found that the culprit was
extra data in the ARP request packets.  The extra data was 802.1p
information, and turning off 802.1p in the driver on the laptop
immediately fixed the issue.

I think it's _good_ that firewalls are picky about layer 2 data, but
figured it'd be good to have in the archives should someone not be able to
ping their firewall and not have a sniffer handy.

Paul
-----------------------------------------------------------------------------
Paul D. Robertson      "My statements in this message are personal opinions
paul () compuwar net       which may have no basis whatsoever in fact."
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