Gentoo Archives: gentoo-user

From: Grant <emailgrant@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Sharing an internet connection
Date: Fri, 13 Mar 2009 00:42:57
Message-Id: 49bf44f10903121742j3976ededqb67b5a182ffcb1@mail.gmail.com
In Reply to: Re: [gentoo-user] Sharing an internet connection by Dan Farrell
1 >> I travel with a strong external antenna for picking up faint wireless
2 >> signals.  It works great, but my girlfriend struggles to connect with
3 >> her built-in antenna.  I do have a travel router (D-Link DWL-G730) so
4 >> I'd like to be able to do something like this:
5 >
6 >> WAN->my laptop->travel router->girlfriend's laptop
7 >
8 > That sounds right to me.  Read on...
9 >
10 >> I use wicd and I'm not sure how to go about this, especially since my
11 >> laptop DHCPs for an IP from the WAN so I'm not sure how to define the
12 >> gateway for the travel router when following this:
13 >
14 > I don't have experience with wicd or the DWL-G730, but I did do a
15 > little research on those and have suggestions.
16 >
17 > If I were setting this up myself it would be with another Wifi card in
18 > AP mode, which I'd be running DHCP on.  In that case, the client (in
19 > this case your girlfriend's laptop) would be given a DHCP address and a
20 > default route of my AP's address.  Alternately I might forego the DHCP
21 > server setup and instruct the client to set a particular IP and route
22 > (the route would be my AP's IP).  In either case, nameservers could be
23 > copied directly from "my laptop" to the client's, or "my laptop" could
24 > supply its own IP for nameserver and provide DNS service or proxy
25 > itself.
26 >
27 > "My laptop" would then have a route through the AP for internal traffic,
28 > and use the (dhcp provided) default route for other traffic.
29 > Therefore, the AP would never need to specify the IP of the external
30 > connection.
31 >
32 > The client box would route all traffic through the AP's IP so it
33 > wouldn't need to know the external IP either.
34 >
35 > "My laptop" would have to run IPTables for NAT.  You'll need network
36 > address translation because external IPs like websites won't be able to
37 > route to the client box's IP.  NAT gets around this.
38 >
39 > The AP provided by "my laptop" must also be on a different subnet than
40 > the external network "my laptop" is connected to.  If "my laptop" was
41 > connected to an access point offering a 192.168.1.0/24 subnet, for
42 > example, a seperate subnet like 192.168.2.0/24 ought to be used on the
43 > "client side" of "my laptop".  Personally I'd probably use an rfc class
44 > b subnet since they're rare, or another rare subnet like
45 > 192.168.66.0/24.
46 >
47 >> http://www.gentoo.org/doc/en/home-router-howto.xml
48 >>
49 >> Is there a simple way to pull this off?
50 >
51 > In short, no, but it's not too complicated, and the home router guide
52 > will help you, but using your travel router may make things more
53 > complicated.  The travel router probably will itself provide NAT and
54 > DHCP so I'm not sure without playing with one how it would look to set
55 > it up that way.  You might want to provide those services yourself and
56 > use the travel router as an AP instead.
57
58 Thanks Dan. No matter what I do, I can't get the other laptop to
59 communicate with my laptop. It can ping the router which is between
60 us, but it can't get to the other side. I've got dnsmasq and
61 shorewall running on my laptop. Any idea what the problem could be?
62
63 - Grant

Replies

Subject Author
Re: [gentoo-user] Sharing an internet connection Dan Farrell <dan@×××××××××.cx>