Hi! Some general question + Wifi USB Realtek RTL8191S

[matzi]

The Output is:

root@fvdwsl-base:/ # busybox route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.178.1 0.0.0.0 UG 0 0 0 eth0
192.168.178.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

I am not familiar with route instruction. Obviously a rule for wlan0 is missing. Shall I add a copy of the two existing lines changing eth0 by wlan0? If so, how were the existing entries created? I never used route command before.

[Jocko]

Hi matzi,

Indeed, some routes are missing for wlan0.

You must add two routes :
- default route for WAN connection (need a gateway)
- route for LAN address (gateway is useless). It's amazing that this route is not created when you configures wlan0 :dry because it's the default behaviour with an Ethernet NIC.

So do these commands

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route add -net 192.168.178.0 netmask 255.255.255.0 dev wlan0
route add -net 0.0.0.0 gw 192.168.178.1 dev wlan0

Now, you should keep an active connection when you unplug the network cable of eth0 :-D

For deleting a route, the commands are
with the default route

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route del -net 0.0.0.0 dev wlan0

and for LAN address

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route del -net 192.168.178.0 netmask 255.255.255.0 dev wlan0

Note: no need to use 'busybox' in these commands because a symlink already exists

[matzi]

I tried the proposal with the routing table. But no success. Still the same behaviour. I noticed that the routing table looses an Entry after unplugging the cable (see below):

Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.178.1 0.0.0.0 UG 0 0 0 eth0
192.168.178.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.178.0 0.0.0.0 255.255.255.0 U 0 0 0 wlan0

it looses the line with :
0.0.0.0 gw 192.168.178.1 wlan0

Remark: I'm pretty sure the dongle itself is OK, because it is running in my raspberry pi without a problem in wpa encryption.

[fvdw]

maybe Jocko knows a next step

ps what happens if instead of unplugging you bring down the interface
so

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ifconfig eth0 down

[Jocko]

Yes fvdw,

Bring down eth0 should force the firmware to use wlan0.

Other idea that I must deepen, currently you have the same metric for the two NIC. So maybe increase metric for eth0 will do the same thing than bring down eth0.

You can also check you route table with the command traceroute

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traceroute -i iface 192.168.178.xx

where iface is eth0 or wlan0 and 192.168.178.xx another host of your LAN

[matzi]

A small progress step but still confusing:

When I do the sequence "eth0 down" and then unplug the cable, the wireless connection persists. Strange thing it is persists under wireless and also under the wired IP!

Traceroute gives:
root@fvdwsl-base:/ # traceroute -v -i wlan0 192.168.178.20
traceroute to 192.168.178.20 (192.168.178.20), 30 hops max, 38 byte packets
1 192.168.178.20 (192.168.178.20) 46 bytes to (null) 9.239 ms 5.436 ms 11.794 ms




Routing table in this state is:
root@fvdwsl-base:/ # route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.178.17 0.0.0.0 UG 0 0 0 wlan0
192.168.178.0 0.0.0.0 255.255.255.0 U 0 0 0 wlan0

(I used a different router with IP ending 17)

[Jocko]

Hi matzi,

Currently I am playing with an USB LAN adapter and so some similar issues than you.

With my test, set a metric doesn't change the default behaviour : eth0 is always used. Only bringing down eth0 allows to use the additional NIC.

So you can do it but be careful if wlan0 is not rightly set you will lost all access and you should reboot your NAS.

Note : if you bring up again eth0 only route for your LAN is restored you must manually add the default route (with the gateway) for eth0

---about your last post---

Traceroute gives:
root@fvdwsl-base:/ #

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traceroute -v -i wlan0 192.168.178.20
traceroute to 192.168.178.20 (192.168.178.20), 30 hops max, 38 byte packets
1 192.168.178.20 (192.168.178.20) 46 bytes to (null) 9.239 ms 5.436 ms 11.794 ms


Routing table in this state is:

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root@fvdwsl-base:/ # route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.178.17 0.0.0.0 UG 0 0 0 wlan0
192.168.178.0 0.0.0.0 255.255.255.0 U 0 0 0 wlan0

this means that your wlan NIC runs well

But about your amazing test

When I do the sequnce "wlan0 down" and then unplug the cable, the wireless connection persists. Strange thing it is persists under wireless and also under the wired IP!

after doing ifconfig wlan0 down, did you check if wlan0 was really bring down ? if it is still listing with

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ifconfig

then the command failed
---edit---
and also its routes must disappear in the route table.

Maybe you must use iwconfig to do it

[matzi]

Excuse me in my last post it should read of course "after eth0 down"

eth0 is down, see below complete output of ifconfig:

root@fvdwsl-base:/ # ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:4666 errors:0 dropped:0 overruns:0 frame:0
TX packets:4666 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:632383 (617.5 KiB) TX bytes:632383 (617.5 KiB)

wlan0 Link encap:Ethernet HWaddr 7C:DD:90:17:C3:09
inet addr:192.168.178.21 Bcast:192.168.178.255 Mask:255.255.255.0
inet6 addr: fe80::7edd:90ff:fe17:c309/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3483 errors:0 dropped:0 overruns:0 frame:0
TX packets:1941 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:588915 (575.1 KiB) TX bytes:282726 (276.0 KiB)

[Jocko]

I edit my previous post...

[matzi]

Yes I fully agree with your last post. Just a short moment before your post I tried to explain mine....
So I just did what you proposed yesterday. When both connections are up, then set eth0 down. That worked so far. Strange is the persisting IP of the wired connection.