Web lists-archives.com

Re: pointers to material for using netbook's wireless as access point

I posted the following to Randy, yesterday, intending it to go to the list.
I'll post it back to the list (with Randy's permission), with a bit of further

> On Friday, June 09, 2017 02:14:17 AM Joel Rees wrote:
>> (With aplogies for html mail)
>> 2017/06/08 23:46 <rhkramer@xxxxxxxxx>:
>> > On Thursday, June 08, 2017 10:00:17 AM Joel Rees wrote:
>> > > Maybe I'm misunderstanding that wiki, but it seems to be describing
>> > > this
>> > >
>> > > kind of setup:
>> > >    WAN <--> foreign AP <-wireless-> debian box <-> more devices
>> > >
>> > > But what I'm wanting is
>> > >
>> > >    WAN <-wired-> router/modem <-wired-> debian netbook AP <-> more
>> devices
>> > Thank you for including the above "sketch" which finally let me
>> understand what
>> > you are looking for.
>> >
>> >  I doubt that I can help, but I'll think about it--my setup is somewhat
>> >
>> > similar to what you describe except that the "debian notebook AP" is
>> replaced
>> > by a commericial wireless AP (but, as your sketch shows, wired to my
>> router /
>> > modem).
>> >
>> > Aside: I wouldn't think it should be very difficult, since it seems to be
>> off-
>> > the-shelf functionality you can buy, but ...
>> Thanks for looking at it.
>> Just for the record, I am presently typing on my tablet, connected wireless
>> through the
>> software AP in the netbook (which is the reason for the html). It's
>> transparent, so the
>> modem at the wall sees it as if the wireless is an extension of the modem's
>> (wired)
>> network.

And this is kind of tricky, because it seems to be a bit dependent on the
weather, whether it works or no.

Or, rather, I have since installed dnsmasq and removed and re-installed
network-manager (stupid thing gets in the way), and I'm not connecting
any more.

>> What I'm trying to get is connection on the netbook itself. I can't even
>> ping the modem
>> from the netbook, because the bridge owns the netbook's only ethernet port.
>> So I can't
>> work on anything that requires the network while the kids are playing.
>> I read hints here and there about how to do it, but I keep hitting walls.
>> (And learning
>> things. :)
>> I had it serving dhcp and dns over the wireless a bit back, but I couldn't
>> get outside the
>> modem with either the wireless or the netbook. That was not, of course,
>> bridged. I think.

I was able to confirm that it was bridged.

>> 8-/
>> It would be cheaper, time-wise, to buy a portable access point, of course,
>> and I will probably do so.
>> But I'm finally getting an idea of how a bridge really works, so it's also
>> worth the
>> education.
>> Joel Rees

Randy replied,

On Fri, Jun 9, 2017 at 9:43 PM,  <rhkramer@xxxxxxxxx> wrote:
> This provides me with even more understanding of what you're looking for and
> the problems you're having--up until I read this, I didn't understand that (1)
> the netbook is already working "properly" as a wireless access point (in that
> your tablet wirelessly connects via it), but (2) the problem is that the
> netbook apparently can't be used simultaneously as a WAP and to provide its
> own connection to the Internet.
> I would suggest that you post this to the list--I think others may have the
> same misunderstanding as to your goal and the current problem, and once
> understanding this, may be able to help you.
> If you want, I can post it to the list as well.
> I would tend to say that your problem is not a common problem, so I suspect
> most documentation won't be helpful.  I also tend to doubt that you want the
> netbook to be in bridge mode, but I don't know that for sure.  IIRC (and I
> can't easily check at the moment), I believe my (commercial) WAP is working as
> a full fledged router, in the sense that it creates a new network (with a
> different IP address and provides DHCP functionality).  I'll have to turn my
> WAP on later and see what IP address my phone gets to see if it is on my "main
> LAN" (i.e., wired) or if it is an IP on a different network.
> Good luck,
> Randy Kramer

Indeed, that's what I want to do. But I'm not smart enough to set the wireless
up myself, so I was hoping hostapd would do that.

On Fri, Jun 9, 2017 at 10:30 PM,  <rhkramer@xxxxxxxxx> wrote:
> Update: I just turned on my WAP and my cell phone, and found that the cell
> phone gets an IP address in the 10. network (specifically, in this case
>, while my "main" (wired) LAN is on the 192.168.1 network (the server
> is, thus confirming my suspicion that the WAP is not in bridge
> mode, but is a "full" network server with services such as DHCP.

That is the usual case for portable access points in Japan. (And, unless you
ask, they don't tell you that you can log into the admin page and set the
number of devices that can connect wirelessly to the AP.)

> I guess if you're in bridge mode, the IP address of your tablet is coming from
> your modem / router.

That is correct. It was getting addresses in the range the wall modem was
providing. A couple of time it got addresses in the range that my netbook
was providing (dhcpd), but I wasn't serving dns through the port. Apparently,
it was not routing to the modem. (I don't have enough working computers to
check the connections any more, and the kids don't like me to take theirs
over to test things.)

> Digression: I actually usually have my DSL modem in bridge mode so that the
> next  device in my network string (a Ubiquity router) actually serves as the
> network server (with DHCP and such).  While in bridge mode, the DSL modem is
> pretty dumb--I can't connect to it or such.  When I have troubles with my
> Earthlink ISP, they typically want me to switch back out of bridge mode to
> (they think) help with diagnosis.  (Aside / rant: In no case have my troubles
> with Earthlink been inside my network, they have always been external, one way
> or another, but Earthlink likes to assume that the trouble is inside my
> network.  What a PITA.)

(Until we get Microsoft -- and now Google? -- to quit wanting to sell us the
privilege of helping ourselves, we won't have enough people in customer
service who really know what they are doing to avoid this kind of two-step
dance they want to do, I think.)

> Also, bridge mode in networking may have two slight different meanings
> depending on the context--I don't think I can articulate that very well.
> Putting my DSL modem in bridge mode makes it pretty much a dumb box, passing
> Internet traffic thru to my Ubiquity router (in both directions)--at that time,
> the Ubiquity router is the "brain" of my network.  Ubiquity also has a means
> to set some sort of bridge mode for devices or networks downstream of it, but
> I don't really know what that does, but it seems a little different than the
> bridge mode of the DSL modem.  (I've never experimented with it, or maybe only
> enough to realize it was not what I needed.)

There definitely seem to be both blind and intelligent bridges.

When I was reading about the split horizon yesterday, I was wondering
whether bridges could actually be used by the computer they are
connected to, but, if that were the case, hostapd could not really work
at all. I think.

It may be that I will have to go down to the coding level, or give it up.

And then I figured out, this morning, that something is preventing me
from configuring the NIC's network as precisely as I am trying to do.
Maybe that's the re-installed network-manager.

Joel Rees

One of these days I'll get someone to pay me
to design a language that combines the best of Forth and C.
Then I'll be able to leap wide instruction sets with a single #ifdef,
run faster than a speeding infinite loop with a #define,
and stop all integer size bugs with a bare cast.

More of my delusions: