dgerow at afflictions.org
Fri Mar 25 20:34:04 PST 2005
Thus spake Bill Stewart (bill.stewart at pobox.com) [25/03/05 17:23]:
: If you're in range for 100 meters at a 18kph city crawl (or bike)
: that's about 5 meters/sec so you've got 20 seconds, and it can work.
: If you're driving 90kph and catch 10 meters of the edge of a range,
: you've got 0.4 seconds to do the job, which is pretty dodgy -
: lots of mail servers take a few seconds to really sync up,
: especially if you've got to do a DNS lookup or two.
Bike would be more likely than car. Or even walking. Modify your mode of
transportation to meet your needs; don't try to cram near-impossible
technological feats to meet your mode of transportation.
In theory, all you're doing is:
- Finding an AP
- Associating with the AP
- this could mean just setting your SSID, it could mean cracking WEP
keys, it could mean providing authentication...
- Grabbing an address (DHCP)
At this point, you're looking at around five seconds of work. Which, at the
aforementioned 18kph, gives you another 15 seconds to send off any mail.
If you run a local DNS server (faster), you'll save yourself a few seconds.
The actual MTA transmission only takes a few seconds; that is, unless you're
spamming, in which case it may take longer.
If you're sending out via something that encrypts and authenticates, it
might take a bit longer. All the same, 15 seconds is plenty time to get off
at least a few messages. At which point, you just keep on moving, and let
your gear find a new AP, and start all over again.
: Directional Antennas are unlikely to be useful -
: if you've got them aimed right, you might win,
: but you're much more likely to miss entirely
: or have only a few meters that you're in range.
Directional antennas would be pointless. Go for a high-gain
omnidirectional. You might lose a little range, but it's highly unlikely
you'd be able to gain anything from the range.
Plus, I'm assuming a secondary goal would be indiscretion: someone walking
down the street pointing three duct-taped together Pringles cans at people's
houses probably isn't terribly indiscrete. It'd be much better to just keep
a larger omni antenna in the bag on your back (with the
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