Question on public WIFI access points

I'm in a hotel that provides WIFI Internet access. They have a number of
access points which run unencrypted. My initial attempts to connect to it
through Linux were unsuccessful. I was able to scan the access points
through iwlist but DHCP couldn't get an IP address. I then booted into XP
and used a Broadcom utility to find the access points and to attach to one
of them. After I did that a web based registration page popped up which
asked for my name and company. It also had an option to assign an IP
address to me. I did all that and then rebooted Linux (FC5). DHCP worked
at that point and I was able to get to the Internet. I'm assuming that
when I registered and asked for a IP address it took my MAC address and
put it into a table along with the assigned IP.

My questions are,

1) How did Windows access that registration page?

2) Was the communication with the access point MAC based prior to my
asking it to assign an IP address? What protocol was used?

3) Is there some way to do this registration from Linux?

On Wed, 25 Oct 2006 10:25:20 -0400, General Schvantzkoph wrote:

> I'm in a hotel that provides WIFI Internet access. They have a number of
> access points which run unencrypted. My initial attempts to connect to it
> through Linux were unsuccessful. I was able to scan the access points
> through iwlist but DHCP couldn't get an IP address. I then booted into XP
> and used a Broadcom utility to find the access points and to attach to one
> of them. After I did that a web based registration page popped up which
> asked for my name and company. It also had an option to assign an IP
> address to me. I did all that and then rebooted Linux (FC5). DHCP worked
> at that point and I was able to get to the Internet. I'm assuming that
> when I registered and asked for a IP address it took my MAC address and
> put it into a table along with the assigned IP.
>
> My questions are,
>
> 1) How did Windows access that registration page?
>
> 2) Was the communication with the access point MAC based prior to my
> asking it to assign an IP address? What protocol was used?
>
> 3) Is there some way to do this registration from Linux?

I'm no expert, but I think the answers depend. A year or so ago I did a
demo at a local hotel using a linux laptop (atheros chipset wifi card) and
it did pretty much what you described - I think it probably depends on the
installation.

On Wed, 25 Oct 2006 10:25:20 -0400, General Schvantzkoph wrote:

> I'm in a hotel that provides WIFI Internet access. They have a number of
> access points which run unencrypted. My initial attempts to connect to it
> through Linux were unsuccessful. I was able to scan the access points
> through iwlist but DHCP couldn't get an IP address. I then booted into XP
> and used a Broadcom utility to find the access points and to attach to one
> of them. After I did that a web based registration page popped up which
> asked for my name and company. It also had an option to assign an IP
> address to me. I did all that and then rebooted Linux (FC5). DHCP worked
> at that point and I was able to get to the Internet. I'm assuming that
> when I registered and asked for a IP address it took my MAC address and
> put it into a table along with the assigned IP.
>
> My questions are,
>
> 1) How did Windows access that registration page?
>
> 2) Was the communication with the access point MAC based prior to my
> asking it to assign an IP address? What protocol was used?
>
> 3) Is there some way to do this registration from Linux?

I was able to access the registration page when running W2K in a Parallels
VM on top of FC5. The behavior was identical to that of native Windows,
i.e. when I opened up Firefox the registration page was there. After I had
it assign an IP to me I was able to do an ifup wlan0 and then access the
Internet from Linux. Bringing up native Firefox on FC5 didn't get anything.

So now I'm even more confused, how is Windows making the connection to the
registration web page before the IP is assigned? Windows had to go through
Linux to get to the WiFi hardware, so it must be possible to do the same
thing natively. Does anyone have any theories?

General Schvantzkoph <(E-Mail Removed)> writes:

>I was able to access the registration page when running W2K in a Parallels
>VM on top of FC5. The behavior was identical to that of native Windows,
>i.e. when I opened up Firefox the registration page was there. After I had
>it assign an IP to me I was able to do an ifup wlan0 and then access the
>Internet from Linux. Bringing up native Firefox on FC5 didn't get anything.

>So now I'm even more confused, how is Windows making the connection to the
>registration web page before the IP is assigned? Windows had to go through
>Linux to get to the WiFi hardware, so it must be possible to do the same
>thing natively. Does anyone have any theories?

Watch the traffic in both cases with tcpdump to see what the diff is;

I was once in a hotel in NL where I got an IP from AP but could not
go nowhere with KDE/FreeBSD Konqueror; I already wanted to give up
when a colleague said: fire up Firefox. I did so and put it some URL
and magically came up the login page of the provider for paying
the fee and after that everything worked. I watched as well with
tcpdump and saw that Firefox, before going to the URL, wanted to phone
home and this DNS request was answered by the AP/provider, while all others
DNS request were not. Bottom line: somehow the providers know what
certain system is doing first and combining that with the login
logic.

Bad world :-((

matthias
--
Matthias Apitz
Manager Technical Support - OCLC PICA GmbH
Gruenwalder Weg 28g - 82041 Oberhaching - Germany
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e <(E-Mail Removed)> - w http://www.oclcpica.org/ http://guru.UnixLand.de/