Router problems on Redhat 9.0 Linux 2.4.20-13.9.HOSTAP

Wed Apr 28 00:19:49 UTC 2004

On April 27, 2004 06:38 am, Yann Garcia wrote:
> -----Message d'origine-----
> De : Pete Nesbitt [mailto:pete at linux1.ca]
> Envoyé : mardi 27 avril 2004 03:49
> À : yann.garcia at smartcom.com; General Red Hat Linux discussion list
> Objet : Re: Router problems on Redhat 9.0 Linux 2.4.20-13.9.HOSTAP
>
> On April 23, 2004 01:36 am, Yann Garcia wrote:
> ...
>
> > > > On April 15, 2004 12:21 am, Yann Garcia wrote:
>
> <snip snip snip>
>
> > Hi Pete,
> >
> > My problem is that I can't ping machine in the LAN from the WLAN. I
> > start tethereal on each network interface on my linux box (eth0 &
> > wlan0). When I try to ping a machine on the LAN from the WLAN, I can
>
> see
>
> > the ping request on the wlan0 interface. But I don't see anything on
>
> the
>
> > eth0 interface.
> >
> > Yes, the machines on the wireless network have the default gateway of
> > 10.1.10.1, while the machines on LAN including the linux box/router,
> > have 10.0.0.1 as the gateway.
> >
> > From the linux box, I can ping the gateway and all other machine in
>
> the
>
> > LAN.
> > But from the WLAN, I can only ping the linux box interface eth0. I
>
> can't
>
> > ping the gateway 10.0.0.1 and I can't ping any machine in the LAN.
> >
> > Yes, the ip_forwarding is set:
> > [root at hotspot root]# cat /proc/sys/net/ipv4/ip_forward
> > 1
> >
> > Here is the output of ifconfig:
> > eth0      Lien encap:Ethernet  HWaddr 00:08:74:C2:93:35
> >           inet adr:10.0.1.37  Bcast:10.0.255.255  Masque:255.255.0.0
> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> >           RX packets:200395 errors:0 dropped:0 overruns:0 frame:0
> >           TX packets:10625 errors:0 dropped:0 overruns:0 carrier:0
> >           collisions:0 lg file transmission:100
> >           RX bytes:36890115 (35.1 Mb)  TX bytes:818892 (799.6 Kb)
> >           Interruption:11 Mémoire:dd000000-dd001080
> >
> > lo        Lien encap:Boucle locale
> >           inet adr:127.0.0.1  Masque:255.0.0.0
> >           UP LOOPBACK RUNNING  MTU:16436  Metric:1
> >           RX packets:644548 errors:0 dropped:0 overruns:0 frame:0
> >           TX packets:644548 errors:0 dropped:0 overruns:0 carrier:0
> >           collisions:0 lg file transmission:0
> >           RX bytes:44069581 (42.0 Mb)  TX bytes:44069581 (42.0 Mb)
> >
> > wlan0     Lien encap:Ethernet  HWaddr 00:09:5B:91:54:AE
> >           inet adr:10.1.10.1  Bcast:10.1.10.255  Masque:255.255.255.0
> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> >           RX packets:2162741 errors:0 dropped:194 overruns:0 frame:0
> >           TX packets:10994 errors:16 dropped:0 overruns:0 carrier:0
> >           collisions:0 lg file transmission:100
> >           RX bytes:14323112 (13.6 Mb)  TX bytes:1641798 (1.5 Mb)
> >           Interruption:5 Mémoire:d0935000-d0936000
> >
> > Yann Garcia
> >
> > Hi Yann,
> > If you can ping 10.0.1.37 from the WLAN, then your Linux box is routing.
> > What is the error message that the wlan machines receive when the ping
> > fails?
> > You may want to try running tcpdump on the eth0 and check
> > /var/log/messages
> > for any FW generated errors messages.
> > --
> > Pete Nesbitt, rhce
> >
> >
> > Hi Pete,
> >
> > The error message when I ping a LAN machine (the gateway for instance)
> > from a WLAN machine is 'Time exceed'.
> >
> > I run tcpdump on eth0 and I make a ping from WLAN to LAN and I have net
> > error on /var/log/messages: there are no messages between the both
> > messages 'device eth0 entered in promiscuous mode' (tcpdump started) and
> > 'device eth0 left promiscuous mode' (tcpdump stopped).
> >
> > Cheers,
> >
> > Yann
>
> Hi Yann,
> looking over this again, the linux box is 10.0.1.37 on the LAN side. The
> machines on the LAN must have an additional gateway to get to the WLAN,
> that is why you get a time-out, because the packet never returns.
> So try adding this network route to the LAN machines:
> route add -net 10.1.10.0 netmask 255.255.255.0 gw 10.0.1.37
>
> --
> Pete Nesbitt, rhce
>
> Hi Pete
>
> Sorry, I'm not sure to understand: I have to add this new rule on the linux
> box or on the router of the LAN part? I try to add this route on the linux
> box and now when I try to ping a machine in the WLAN part (as 10.1.10.2 for
> example), I have the ping error ' Destination Host Unreachable'. The route
> table is now:
>
> Destination   Passerelle    Genmask         Indic   MSS Fen├¬tre irtt Iface
> 10.1.10.0     10.0.1.37     255.255.255.0   UG        0 0          0 eth0
> 10.1.10.0     0.0.0.0       255.255.255.0   U         0 0          0 wlan0
> 10.0.0.0      0.0.0.0       255.255.0.0     U         0 0          0 eth0
> 169.254.0.0   0.0.0.0       255.255.0.0     U         0 0          0 wlan0
> 127.0.0.0     0.0.0.0       255.0.0.0       U         0 0          0 lo
> 0.0.0.0       10.0.0.1      0.0.0.0         UG        0 0          0 eth0
>
> Cheers,
>
> Yann

Yann,
you want to have this route on all the machines in the LAN, so they know to 
use the Linux box as the gateway to the WLAN. It is not necessary on the 
Linux box (that connects the 2 networks). When you have that in the 
Linux/gateway/router it messes it up as it says to "go out eth0 to get out 
wlan0", which fails.

So, delete the route you added to the Linux box as:
10.1.10.0     10.0.1.37     255.255.255.0   UG        0 0          0 eth0

and add to each other system on the LAN (10.0.1.0). It should also be on the 
default gateway, just not on the Linux box joining the LAN & WLAN. I do not 
know how to do this on a Windows box, but you can use the line from the 
previous post to add it on any Linux boxes (other than the one acting as a 
router between the 2 networks).

Once this is working, you'll want to add it via rc.local to make it a static 
route.

-- 
Pete Nesbitt, rhce