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From: Geoffrey S. Mendelson on 26 Oct 2009 14:04
Amanda Ripanykhazov wrote:
> More importantly I suspect some loss of sensitivity at the AirPort
> card end along with the possibility which I DO accept that there are
> other strong signals nearby, overloading my computer. If I move my
> computer across a certain room between the place where I have these
> problems and the router, I can almost tangibly see the signal drop off
> at around 25 feet from the router and with nothing significant
> intervening at that point: There are no electrical appliances of ANY
> type nearby! So much so that I have installed and configured another
> router (a Buffalo 80211G) as a DD-WRT_VAP repeater to amplify this
> signal! And cranked the output power up to a legal maximum of 99
> milliwatts.

That may be a problem. If you are listening to music, as it gets louder
it starts to become distorted. The same with radio signals. If you use too
much power for the amplifier in the router to handle properly, the signal
becomes distorted and can not be understood.

25 feet is a good distance for WiFi the claims of 100 meters are almost never
realized. It also depends upon the antenna, the one in a laptop is usually
very small. Polarization matters, in plain English if the antenna is vertical
inside the laptop and horizontal on the router, there will be a significant
loss (26dB, or around 100 times).

If you are using 802.11 N connections, there is a signifcant difference
in the range if you are using 5.8gHz (and it's legal where you are),
then the range will be much less than 2.4gHz.

If you are using microwave oven robustness, try turning it on. If it is on, try
turning it off. It really helps reduce interference from microwave ovens
(and radar), but not from other sources and if there is no interference slows
things down.

I was toying with the idea of doing this with a WRT-150N
> which I have lying around as it probably has better range but I havent
> been able to figure out whether this particular router (a VT1) can be
> set up as a repeater and the DD-WRT forums are a bit quiet on this
> point?
>
> The card is an AIrPort Extreme with Broadcom firmware version BCM43xx
> (4.170.25.8) and I wouldn't have any idea how to update the firmware
> otherwise than through an Apple Update. Is there some way of doing
> this?

Not that I know of. You may be able to do it under Windows but then you
could end up with a level of firmware not compatible with MacOS. Very
unlikely, but I can't say 100% it will work.

>
> Anyway let me try Kismac and see what happens.(I didnt know
> that there was a Mac version of Netstumbler). Computers right next to
> this one can connect properly and this one cannot see enough of a
> signal to assign a DNS. I had been told by Fios that only a full
> digital spectrum analyser can tell me exactly what interference there
> is which might be preventing my computer from accessing my network in
> circumstacnes where occasionally it WILL access a neighbour's one
> instead! I doubt that it is an incorrectly set password on the WEP
> end or this computer wouldnt ever be able to access my network through
> my FIOS router. However I have a linksys VoIP router with no
> encryption on the same network and it has all the same problems as the
> FIOS one does. I am pretty sure I have NO third party firewall.

Is the Linksys router also wireless. Try moving the channel. It would be
best to keep them at least 2 apart, e.g. 1 and 3, 2 and 4, 1 and 13, etc.

You could also try turning off the encryption and any authorization if you
have it on, MAC address filtering, etc. If that works you can turn on
what you need.

Make sure that the SSID (network name) of the FIOS and Liksys routers are
different (or the same if that's what you want). WiFi is designed so that
all access points (the radio part of a router, for example) in a network
are treated as if they were equal priority. The computer connects to the
one with the strongest signal, no matter which channel it is on.

Unless the VoIP router is set as a passthrough device, it should not have
the same SSID as the FIOS router. IMHO it should not have WiFi enabled
at all.

My guess is that it is set up as a seperate subnet with it's own DHCP server
and so on, and if they both have the same SSID it would really confuse things.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel gsm(a)mendelson.com N3OWJ/4X1GM
From: Geoffrey S. Mendelson on 26 Oct 2009 14:24
Fred Moore wrote:

> Go to the Network prefs pane. Select Using BootP from the Configure:
> popup. Click Apply and see if you can connect. If you do, you can change
> the Configure selection back to DHCP or whatever. Don't ask me why this
> works, but it might. BootP forces the issue somehow.

BootP and the incompatible BootParam where two older methods of assigning
an IP address upon request. Most DHCP servers also support BootP.

DHCP has more features. One of the features of modern DHCP servers is to
verify an address is unused (ping it) before assigning it so that you can
have more than one DHCP server running on the network at the same time,
or a coding error in the control files.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel gsm(a)mendelson.com N3OWJ/4X1GM
From: Amanda Ripanykhazov on 26 Oct 2009 15:44
On Oct 26, 1:42 pm, Fred Moore <fmo...(a)gcfn.org> wrote:
> In article
> <f4bfa8f8-4dee-471c-b861-32f0ec61c...(a)x15g2000vbr.googlegroups.com>,
>  Amanda Ripanykhazov <dmanzal...(a)googlemail.com> wrote:
>
> > Got a problem which has stumped Apple so naturally I turned here.
>
> > My computer wont pick up an IP. It keeps picking up a spoofed one
> > (what Apple calls a self-assigned one)
> > [tale of aggravation and woe omitted  ;)  ]
>
> This is a long shot, but I've seen it work on occassion.
>
> Go to the Network prefs pane. Select Using BootP from the Configure:
> popup. Click Apply and see if you can connect. If you do, you can change
> the Configure selection back to DHCP or whatever. Don't ask me why this
> works, but it might. BootP forces the issue somehow.

I think that is one of the things which the Genius was trying to do in
the Apple Store to connect to their network and then switching back
again. There is an analogous situation whereby when you get an
annoying error message 'cant connect to network' to which you know you
can connect easily, you have to enable WEP, pretend to connect and
then disable it again (or visa versa) to reset what the OS thinks it
knows about how to connect. (I will try this again next time the
connection isnt made for no known reason)
From: Amanda Ripanykhazov on 26 Oct 2009 15:50
On Oct 26, 2:04 pm, "Geoffrey S. Mendelson" <g...(a)mendelson.com>
wrote:
> Amanda Ripanykhazov wrote:
> > More importantly I suspect some loss of sensitivity at the AirPort
> > card end along with the possibility which I DO accept that there are
> > other strong signals nearby, overloading my computer. If I move my
> > computer across a certain room between the place where I have these
> > problems and the router, I can almost tangibly see the signal drop off
> > at around 25 feet from the router and with nothing significant
> > intervening at that point: There are no electrical appliances of ANY
> > type nearby!  So much so that I have installed and configured another
> > router (a Buffalo 80211G) as a DD-WRT_VAP repeater to amplify this
> > signal!  And cranked the output power up to a legal maximum of 99
> > milliwatts.
>
> That may be a problem. If you are listening to music, as it gets louder
> it starts to become distorted. The same with radio signals. If you use too
> much power for the amplifier in the router to handle properly, the signal
> becomes distorted and can not be understood.
>
> 25 feet is a good distance for WiFi the claims of 100 meters are almost never
> realized. It also depends upon the antenna, the one in a laptop is usually
> very small. Polarization matters, in  plain English if the antenna is vertical
> inside the laptop and horizontal on the router, there will be a significant
> loss (26dB, or around 100 times).
>
> If you are using 802.11 N connections, there is a signifcant difference
> in the range if you are using 5.8gHz (and it's legal where you are),
> then the range will be much less than 2.4gHz.
>
> If you are using microwave oven robustness, try turning it on. If it is on, try
> turning it off. It really helps reduce interference from microwave ovens
> (and radar), but not from other sources and if there is no interference slows
> things down.
>
>  I was toying with the idea of doing this with a WRT-150N
>
> > which I have lying around as it probably has better range but I havent
> > been able to figure out whether this particular router (a VT1) can be
> > set up as a repeater and the DD-WRT forums are a bit quiet on this
> > point?
>
> > The card is an AIrPort Extreme with Broadcom firmware version BCM43xx
> > (4.170.25.8) and I wouldn't have any idea how to update the firmware
> > otherwise than through an Apple Update. Is there some way of doing
> > this?  
>
> Not that I know of. You may be able to do it under Windows but then you
> could end up with a level of firmware not compatible with MacOS. Very
> unlikely, but I can't say 100% it will work.
>
>
>
> > Anyway let me try Kismac and see what happens.(I didnt know
> > that there was a Mac version of Netstumbler). Computers right next to
> > this one can connect properly and this one cannot see enough of a
> > signal to assign a DNS.  I had been told by Fios that only a full
> > digital spectrum analyser can tell me exactly what interference there
> > is which might be preventing my computer from accessing my network in
> > circumstacnes where occasionally it WILL access a neighbour's one
> > instead!  I doubt that it is an incorrectly set password on the WEP
> > end or this computer wouldnt ever be able to access my network through
> > my FIOS router.  However I have a linksys VoIP router with no
> > encryption on the same network and it has all the same problems as the
> > FIOS one does.   I am pretty sure I have NO third party firewall.
>
> Is the Linksys router also wireless. Try moving the channel. It would be
> best to keep them at least 2 apart, e.g. 1 and 3, 2 and 4, 1 and 13, etc.
>
> You could also try turning off the encryption and any authorization if you
> have it on, MAC address filtering, etc. If that works you can turn on
> what you need.
>
> Make sure that the SSID (network name) of the FIOS and Liksys routers are
> different (or the same if that's what you want). WiFi is designed so that
> all access points (the radio part of a router, for example) in a network
> are treated as if they were equal priority. The computer connects to the
> one with the strongest signal, no matter which channel it is on.
>
> Unless the VoIP router is set as a passthrough device, it should not have
> the same SSID as the FIOS router. IMHO it should not have WiFi enabled
> at all.
>
> My guess is that it is set up as a seperate subnet with it's own DHCP server
> and so on, and if they both have the same SSID it would really confuse things.
>
> Geoff.
>
> --
> Geoffrey S. Mendelson, Jerusalem, Israel g...(a)mendelson.com  N3OWJ/4X1GM

Yes, I have tried most of that except microwave robustness because all
microwaves are even further away from the point where the WiFi signal
starts to become weak

As to trying to get the 150N to work, I didnt realise that the N
protocol worked at 5.8 GHz?? And had worse range at that frequency? I
wonder how you change this using DD-WRT? (I have never played around
with DD-WRT on the 150N. Maybe I should?) In any event, it may be a
consumer unit, - though it is no Linksys, - and I cant believe that
the Buffalo can be operationally exhausted by my using it at under a
watt?
From: JF Mezei on 26 Oct 2009 16:32
Here is how DHCP works.

When you have a naked system without IP address (which is what happens
when you boot), the system sends an DHCP request.

This is in the form of an ethernet packet with a blank IP address, and
it is broadcasted to everyone on that ethernet segment. The message is
essentially "can anyone give me an IP ?".

Then, DHCP servers on that ethernet segment receive that request and can
send offers for an IP address, addressing them to the computer by
specifying its ethernet address.


The computer then chooses which offer it wants (usually just one offer
is seen) and then confirms it with the DHCP server and after the
confirmation handshake, it can start to use the assigned IP and other
parameters supplied in the DHCP offer.

In practice DHCP failures happen because the initial request never made
it to a server. In other words, when DHCP fails, it is usually because
you have ethernet layer problems. (wi-fi is ethernet level).

And the self assigned IP you get is done by the computer (Apple adoppted
this strategy starting with Mac OS 8.6 ). One reason is that by getting
such an Ip address, it allows the computer to bring up the IP stack,
even of all connection attempts with fail. Many applications can handle
a connection failure, but most would not handle "sorry there is no IP
stack available" gracefully.



Back to your problem. Since you are using Wi-fi, there are many layers
involved to provide what should be transparent carriage of etherhnet
packets over the air (not to be confused with Avian IP transport
protocol http://www.rfc-editor.org/rfc/rfc1149.txt )

While the Apple folks got you to zap many .plists, did anyone mention
KEYCHAIN ? Wi-fi stores your wi-fi authentication in your Keychain
database. (Applications->Utilities->Keychain Access.app )

You might want to go into Keychain Access and delete any wi-fi
authentication records from it.

As someone else mentioned, there are cases where the wi-fi *appears* to
work (you appear connected) but in fact isn't working because only the
bottom most layer got connected and you didn't get to the authentication
phase.

In system preferences -> network, when you click on "Airport", at the
bottom of the pane on the right you have "Advanced". In the "Advanced"
pane, you gave 802.1x tab. You have some profiles there as well, you
may wish to delete them.

You can specify what type of authentication you want. This has to be
compatible with the network you are connecting to.

When I moved from WPA to WPA2 Enterprise on my base station (Cisco), I
had the behaviour you describe. I had to go into the 808.1x tab and
enable LEAP authentication. And that fixed *my* problem.

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