PDA

View Full Version : Wireless bridge mode - does the router "see" the MAC behind it?



Mark Lanctot
2006-08-06, 18:21
I'm experimenting with Linux. I say "experimenting" because I can barely get anything to work so I'm probably going to move on to something else.

Anyway I've got it set up behind my SB3 in wireless bridge mode. It works just fine for Internet access - I downloaded the 160 Ubuntu updates twice without issue, and web browser access is snappy.

However internal LAN access is slow as molasses. I can't reliably get samba file sharing working, and the web pages for internal servers, SlimServer and my router, load one or two images after a minute or so, then just sit there doing nothing.

I've added the Linux PC's IP address to SlimServer's allowed addresses and started and stopped SlimServer to no avail.

But I'm wondering - how does the router see the device attached to the SB-acting-as-wireless-bridge? Does it see its MAC address or that of the SB3? Should I add the Linux PC's MAC address to the list of allowed MAC addresses? (That would involve trying to find a MAC address under Linux which would take me all night at the rate I'm going, but still.) I've set my router to limit wireless clients - should I add one more or does all the traffic "seem" to originate from the SB3?

Thanks.

Mark Lanctot
2006-08-09, 06:12
Bump!

I tried adding the NIC's MAC address to the wireless client MAC address list. My router isn't reporting seeing it, but I'm still having LAN issues so something is going on.

MrC
2006-08-09, 10:20
Mark,

Debug your network troubles at a lower level, since the lowest layers are required to work correctly before higher services can. Forget samba, browsers, etc. for the time being.

This could be a number of problems. Your fast to WAN, slow to LAN speeds can be misleading because your broadband is very speed- limited relative to your 100mbit LAN connections.

First, from all hosts, be sure you can *reliably* ping all other hosts, esp. your linux box to your LAN hosts in question. We know that some packets get there (albeit slowly). Test both default and larger packet sizes (man ping). I'm betting some packets are being dropped. Run ping for a while to be sure you get 100% packet throughput.

Also, immediately after your pings, look at your ARP tables (arp -a). Both Windows and Linux will have this command. Verify that MAC to IP address mappings are all correct.

- The command ifconfig -a will give you the network interface info you desire. How about posting that info, and the ARP info along with a network diagram showing your setup. Include all network info (IP addresses, netmasks, gateway addrs, broadcast addrs).

FYI - here's a long-since fixed bug report I posted a while ago that will give you more info about SB2's bridging:

http://bugs.slimdevices.com/show_bug.cgi?id=2221

Mark Lanctot
2006-08-09, 11:02
Thanks MrC. I was afraid I'd have to resort to low-level diagnostics.

I have some work to do this afternoon and will start attacking this later.

Thanks for your help.

Mark Lanctot
2006-08-09, 17:15
Well cancel the red alert.

As soon as I wire the Ubuntu PC directly into the router, everything works as expected. File sharing from/to, SlimServer web GUI, everything.

This points the finger at the SB3, unfortunately. It's strange - it works fine for Internet access, downloading files at ~315 kB/s, which is more or less my Internet connection at saturation (about 330 kB/s). It's not a speed issue, the SB3 as a wireless bridge is doing something to file sharing packets only.

I really want to get this working. This is the whole reason why I bought a second SB.

I'll check bugzilla and create a new bug if one's not there. What kind of data would be helpful for diagnosis? Ethereal traces? arp outputs? ping times?

Deaf Cat
2006-08-10, 01:27
Hiya :)
Cheers Mark for the link to this thread, I hope you don't mind me joining in a bit, I've tried some pinging:

Laptop = L
Desk top = D

Ping loopback address 127.0.0.1
L - sent 4 received 4 lost 0% average 0ms
D - same

Ping own address
L - same
D - same

Ping gateway
L - sent 4 received 4 lost 0% ave 4ms
D - same ave 0ms

Interesting one..:
Ping other computers IP address
L to D s 4 r 4 l 0% ave 2ms
1ms
3ms
2ms
D to L s 4 r 3 l 25% ave 3ms
s 4 r 4 l 0% ave 2ms
s 4 r 3 l 25% ave 2ms
s 4 r 4 l 0% ave 43ms

Back to work now, more experimenting later, not really knowing much at all about pinging, I would guess there is a bit of a problem when the desk top is talking to the laptop.....

I suppose I should try the SB too - later.

Have you been doing any pinging Mark ?

Deaf Cat
2006-08-10, 01:44
Could not wait:
D pinging SB 4 4 0 1ms
L pinging SB 4 4 0 179ms / 5ms / 7ms

To work :)

Mark Lanctot
2006-08-10, 05:52
Deaf Cat:

Which device is going through an SB as a wireless bridge?

I can recall that ping times through the SB weren't bad, 1-4 ms.

As I said, speed doesn't seem to be the problem, something else is.

Deaf Cat
2006-08-10, 07:46
Ah I'm still at the starting blocks I'm afraid, not got as far a using the SB as a bridge yet, just sorting getting the things talking to each other through the router with no low level cock ups at the moment.

Still getting 25% loss now and then when pinging the laptop from the desk top but the other way around seems fine...???....how does that come to be when the things are using the same path...???

Mark, I take it you get no losses, when pinging?

Mark Lanctot
2006-08-10, 07:50
Mark, I take it you get no losses, when pinging?

No losses that I can recall with the SB as a bridge. It seems the first ping is the longest, something needs to "wake up" to respond to further pings.

tommypeters
2006-08-10, 08:56
BTW, after the original setup you can go back to network setup by holding the LEFT button. But if wireless bridging is turned on I don't see a way to turn it off. Maybe if I would connect it to a wired network so I'm able to select wired networking, then later changing wireless network again - maybe the question bridging yes/no will reappear then...?

Mark Lanctot
2006-08-10, 10:03
BTW, after the original setup you can go back to network setup by holding the LEFT button. But if wireless bridging is turned on I don't see a way to turn it off. Maybe if I would connect it to a wired network so I'm able to select wired networking, then later changing wireless network again - maybe the question bridging yes/no will reappear then...?

If you have enabled wireless but plugged something into the wired port, the question automatically comes up.

tommypeters
2006-08-10, 10:10
OK, so I need to plug something in to be able to turn it off. I'll check if it's enough with just plugging in a cable, or a cable connected to something powered on - I guess the former.

Mark Lanctot
2006-08-10, 10:17
OK, so I need to plug something in to be able to turn it off. I'll check if it's enough with just plugging in a cable, or a cable connected to something powered on - I guess the former.

If you don't have anything plugged in it was never enabled in the first place.

If you ever enabled it in the past, as soon as you unplug the Ethernet cable, wireless bridging is disabled - there's nothing to bridge. I didn't have to disable bridging when I moved the Ubuntu PC but the network found it when I plugged it directly into my router - this means the SB3 is not redirecting traffic to the Ubuntu PC's MAC address through its wired port anymore, even though I never disabled bridging.

tommypeters
2006-08-10, 10:36
When I just plugged in a cable, nothing happened, as you wrote. If it was connected to something powered I got that question, and could disable bridging - which was enabled before.

When I earlier checked "Current Network Settings" it said "Bridge wireless to ethernet: Yes". Now it says no.

It SHOULD not make a difference if nothing is connected to the port, but if it made no difference at all I believe that setting wouldn't be there.

I bought it used, and since it doesn't work as well as my other SB3 I'm checking all settings. Both usually get between 65-80% signal strength, but this one can stutter an lose the connection. I will of course swap the two and see if the placing is the crucial thing, but first I wanted to sync the settings between the two.

joek
2006-08-10, 15:20
In my experience and with some research I don't believe your router will see the MAC address of the network device bridged through your SB3. I've used multiple routers with multiple different bridge wireless clients all with the same results.

I have a Tivo bridged through my SB3 and the router only see's the MAC address of the SB3. The Tivo has a static IP and I have never had a connection problem to it.

In addition, my server is connected to Netgear wireless client (bridge) and you only see the MAC address of the wireless client bridge and not the server.

In this case, you may have problems with a router trying to provide a dhcp ip mapped to a specific MAC address when the device is behind the SB3 bridge.

In small environments, there is no need to use dhcp unless you are moving devices between networks (i.e. laptop).

Mark Lanctot
2006-08-10, 15:28
In this case, you may have problems with a router trying to provide a dhcp ip mapped to a specific MAC address when the device is behind the SB3 bridge.

In small environments, there is no need to use dhcp unless you are moving devices between networks (i.e. laptop).

I'm using a static IP arrangement.

Thanks for the MAC info - that's how I thought it was supposed to work. So I'm still at a loss to explain it.

I should do some troubleshooting, but I'm Linux-ed out right now.