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Brad Fitzpatrick

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Thoughts on wireless networking [Sep. 25th, 2001|12:30 am]
Brad Fitzpatrick
Back from Starbucks. They closed an hour early tonight (pre-school hours?) so I didn't get to play with my wireless card long, but long enough to have some fun....

It turns out Starbucks net access isn't free (duh) ... it's provided by MobileStar, the same people I believe that provided the net access in the hotel room when I was down in San Diego for O'Reilly's Open Source Convention.

I popped in the card and it tried to ifup eth1 ... wasn't configured. Configured it, pop card out and in... ifconfig -a. .. looks ready!

ping bradfitz.com .... I get an IP address, but no echo replies.

Did I forget something? I sniff the network traffic (to see if there is any when I get ping something) and I see a whole bunch of traffic from some dude with remote X connections and telnet sessions. I see his telnet session traffic ... he's using cvs and checking stuff into some repository on his unix machine at home on @home's network. Okay, he's smart enough to use X and cvs but doesn't use ssh? What a fucking dumbass.

But that makes me think ... wireless networking is such a great tool for malicious people. Just go buy a wireless network card away from your house (another state?) with cash so the MAC address can't be traced back to your credit card, then deploy your virus or whatever from almost anywhere.

Moving on... network works. Why can't I use it? Chuck points me to a wireless net access computer & info kiosk thing that has fliers about how to get setup... you have to go to mobilestar.com and register for a half hour of free use, then they charge you either by month or by minute, your choice.

So then I get curious --- was my DNS configured through DHCP, or was I still using my own DNS server?

$ dig @bradfitz.com livejournal.com

Whaddya know? DNS works. So their router lets all UDP/TCP on port 53 through, but blocks eveything else except port 80/443 to their own website where you register.

So, now I'm back to my thought I had when I was in San Diego ... I just have to write a proxy (for TCP connections, at least... screw UDP) that will run on port 53 outside their network, then write a user-space network driver that connects to that ip/port, sends an IP/port to connect to, then just copies all traffic back and forth. Seems easy. Now I just have to go find the userspace network tool that the RFC 1149 people used... plenty of userspace filesystem stuff out there.

End result: free Starbucks net access! (if I'm motivated to actually do it... :-P)

Update: Here's the RFC 1149 implementation. Just need the "Universal TUN/TAP Interface as a module".... CONFIG_TUN=y ... "alias char-maj-10-200 tun"... (notes to myself, more than anything)

Update 2: I think I can just use vtun!
LinkReply

Comments:
[User Picture]From: dethbunny
2001-09-25 01:01 am (UTC)

Deja-vu

I *swear* I've read the second half of your post before. Like somebody else had the exact same plan. Maybe it was on /. or something...
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[User Picture]From: brad
2001-09-25 01:04 am (UTC)

Re: Deja-vu

Dude, I said it a few months ago when I was in San Diego:

http://www.livejournal.com/talkread.bml?itemid=7553266

Like I said in this post: "So, now I'm back to my thought I had when I was in San Diego ..."
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[User Picture]From: dethbunny
2001-09-25 01:35 am (UTC)

Re: Deja-vu

A hahaha ha ha (I'm dumb) and stuff.

Didn't quite catch that.

Oh, also, I'm an ass monger. For that I apologize. (relating to the memory/cache for that Mac you got...) do you still want that stuff? I put off sending it out for stupid reasons and then forgot about it when moving to a different apartment a month and a half ago...just let me know I'll get it sent out.
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[User Picture]From: brad
2001-09-25 01:59 am (UTC)

Re: Deja-vu

Yeah, that'd rule.

Then it'd have enough memory to load programs!
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(Deleted comment)
[User Picture]From: dethbunny
2001-09-25 01:14 pm (UTC)

Re: Deja-vu

...which means I've read it both places.

The difference between the /. story and Brad's implementation is brad just wants to tunnel traffic over the DNS ports, while the other people actually tunneled through the DNS protocol. More complicated, and slower, but a neater hack in the long run.
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From: ex_candle321
2001-09-25 01:59 am (UTC)
You know Brad that sometimes I read the stuff you write about and I FEEL so old .And I read some more and my brain hurts. .lol
I wish I had just 1/4 of the brain cells you have..But I did get mandrake installed and running so not to bad for an old fart.

Later
Candle
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[User Picture]From: mart
2001-09-25 04:02 am (UTC)

Sheesh, US Starbucks have net access? Our local one barely has coffee access.

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[User Picture]From: starbelle
2001-09-25 04:12 am (UTC)
we don't even have net access at our school.. -_-
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[User Picture]From: jwendl
2001-09-25 06:47 am (UTC)
I wonder why they don't create some sort of vpn connection instead of leaving port 53 open? Of course then again, I really am clueless when it comes to wireless connections.
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[User Picture]From: revjim
2001-09-25 07:24 am (UTC)
Under Debian, you can "apt-get install vpnd". This package does what you would think it would do: allows you to setup a virtual private network. Where it helps you is you can have the server end of it (on your broadband connection at home) listen on port 53 for incoming VPND connections. So, the traffic wont look at ALL like DNS traffic, but as long as they are not content filtering that port, it should work fine. Very easy to set up too. The downside is that all of your traffic will be routed through your broadband connection at home. This can make things slower, but not unbearable. I use a modified version of this setup myself to get external internet access here at work.
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[User Picture]From: deus_x
2001-09-25 07:50 am (UTC)
And of course, there's always SOCKS and SSH port forwarding. It's gotten me through more firewalls than anything else...

Though, I haven't tried vtun in a long time, but if you have Linux on both ends, the virtual PPP tunnel can be nice. I've just had to modify my toolkit to account for different OSen on both sides...
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[User Picture]From: ironman1231
2001-09-25 09:25 am (UTC)
Brad, perhaps you should make this post friends only, since you're talking about hacker-type stuff that *could* be considered a little illegal.
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[User Picture]From: twistah
2001-09-25 06:27 pm (UTC)
Nah, that's what the 1st Amendment is there for.

If people like the Earth Liberation Front (ELF) can get away with 20mb PDF files describing how to properly set fires with electrical timers, Brad can surely post this kind of theory without repercussion.
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[User Picture]From: ironman1231
2001-09-25 11:41 pm (UTC)
It didn't sound like theory - it sounded like criminal conspiracy to defraud Starbucks. I just happen to not want Brad in trouble.
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[User Picture]From: niko
2001-09-25 04:21 pm (UTC)
rock. I so know what I'm gonna do with my friend's powerbook and airport card. :)

wonder how hard it'd be to impliment these ideas under OSX..
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[User Picture]From: twistah
2001-09-25 06:32 pm (UTC)
The worst thing about wireless networking is the plethora of companies that broadcast SSID, refuse to use WEP and the like. Bandwith leeches and other nefarious charachters are out there, some with high-power antennas, doing war driving/floating/peddling. Did you see the one ExtremeTech article that was on /. a while back, about how they "war drove" around New York and California and what they found?
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