a very stange networking problem with a WiFi provider in France


Hello everyone,
Here it is, in a nutshell: this prepaid WiFi provider, Meteor
Networks, allows you to browse fine if you are using Windows yet you
get garbled IP transmissions under Linux - or at least so it seems.
Here's the summary of it:
formatting link

Any help much appreciated.
Thanks.
Boris.
Reply to
borepstein
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" snipped-for-privacy@gmail.com" hath wroth:
The first step to solving a problem is to blame someone. It seems you're blaming the service provider for pandering to Microsoft. That takes care of that problem, so we can move on to a solution.
The problem is that your 2nd hand description of the problem is devoid of any equipment lists, software versions, and configuration information. It doesn't even include which Windoze or Linux mutation is being used. In short, there's no way to determine if there's anything happening in hardware or software. That's because all 802.11 wireless is done on IP layer 2 (MAC layer). Since Linux handles this layer quite differently than Windoze, a Linux configuration or setting error would certainly cause this problem.
The good news is that since your friend didn't provide even the exact error messages he was getting, I'm relieved of the responsibility of providing a detailed and exact answer. Therefore, I can guess(tm). My guess is that there's something screwed up in the Linux wireless driver or MAC layer configuration. It could also be in the access point. Perhaps the Meteor network is using flow control and his Linux setup is ignoring the management packets. No way to tell from here.
Instead of fixing the problem, it would be most interesting to see if the problem is unique to Meteor. As your friend to drag his laptop to some other hotspot and see if the problem persists. Your article doesn't indicate if he's done any testing at other hot spots using Linux.
The "missing blocks of web pages" is fairly common with a weak signal or in a high interference environment. The browser simply gives up trying to load some external URL's on the page and instead supplies a blank box. This is considered acceptable instead of the alternative, which was formerly to sit forever and wait for some obscure external URL to load. I suggest you interrogate your friend for signal strength, signal to noise ratio (or noise level), and connection speed.
Have him also run a continuous ping test to the wireless router and look for wide variations in latency. It should be fairly low (2-8msec) and fairly consistently the same value. If not, he has packet loss, interference, a weak signal, or all the aformentioned.
If you have any furthur questions, please include the missing models, versions, error messages, signal readings, and settings. Also, don't forget to include the requisite "it's all Microsoft's fault" or "Linux rules" in your reply.
Reply to
Jeff Liebermann
Wasn't the trademarked by Radio Shack?
Oh, no...they used "You got questions? We got blank stares"
It was IBM that copyrighted "This page left intentionally blank".
Reply to
DTC
Hi Jeff,
Thanks for your response, though I must say it is a rather strange one. See my comments below.
Boris.
Well... are you projecting?
No, I am not seeking someone to blame when I encounter a problem. I analyse the problem and then - if evidence points to any particular factor as being the culprit - only then do I blame this factor. Often - just as here - in a hypothetical way.
Now as for details, we have a dual boot SuSE Linux 10.1/Windows XP laptop that here in Boston does networking just fine, both WiFi (at the owner's home) and Ethernet when he brings it to the office under both OS's. Then he goes to Paris and at the hotel his laptop connects just fine under Windows but has severe problems accomplishing this feat under Linux. Is it so wrong after all this to hypothethize that Windows (or something related thereto) may be at fault here?
Well, my description is certainly somewhat short on detail, that is valid criticism. I am not 100% sure what the differences are in the MAC layer transport handling between Windows and Linux but from my extensive experience with Linux I must say I never experienced any problems with the Linux implementation. And, like I said before, that Linux box does WiFi just fine on the regular basis.
You were never under any obligation to start with. Participation in newsgroups like this one is entirely voluntarily. And I do thank you for taking the time to try and help me here:)
Like I said, he uses WiFi on the regular basis.
Well, would the signal-related characteristics vary wildly depending on what OS you have booted? I would think that unlikely.
Makes sense, we may do that should there be a need.
It is not about that - it's about fixing the problem. Now as for a more realistic scenarion - someone has suggested to me on a different discussion board that possibly Meteor scans machines for open ports and tries to block those that have open ports which in their opinion makes them a potential server. I think that is plausible - so I emailed him asking him to turn the firewall on and see what happens.
We'll see.
Reply to
borepstein
So your help to someone using wifi didn't include using a firewall FROM THE START?
Perhaps your consulting is questionable, at best.
Reply to
Bill Kearney
Perhaps, and I never positioned myself as a WiFI expert. Then again, most of the time he does WiFi at home with WEP, and all that is open on the machine is SSH (no Telnet, FTP or other unsafe protocols as near as I remember). So this is not a glaring security issue.
Reply to
borepstein
All my responses are strange. What I lack in diplomacy, I make up in experience, technical expertise, and insults.
Nope. Kindly explain the title of your blog entry: "Web-pandering to Mr Gates or..." I'm certainly no fan of Microsoft business practices. However, the title is not particularly relevant to any part of your blog entry. It's also misleading as the "or..." part implies there's more to the connection between Mr Gates and your friends problems. Change the title and I don't have a problem.
The blog title suggests otherwise. The title of your usenet news article also suggest a culprit, but it less definitive in that it doesn't actually blame Mr Gates. Hint: It's only a "strange problem" until you find the answer.
Easy. You make the assumption that whatever he's trying to accomplish in France should be identical in function to doing the same thing in the USA. That's often not the case, as different systems block or throttle specific ports. Authentication is sometimes a problem. The number of open outgoing TCP sockets are sometimes restricted. Lots of possibilities that need to be checked. I'll grant you that things should work identically in two different countries, but there's no guarantee.
I had a similar adventure with a friend using XP SP2 in France. She was using the MS Language bar and automatically changed to French when she arrived in Paris. That screwed up all her email settings, and automatically switched her to an old Earthlink network setup that we thought had been vaporized. I spent an hour on the phone trying to figure what had changed. Switching back to English solved most of the problems (except for the timezone). The moral is to not make assumptions, they're usually wrong.
There are substantial difference between Linux and Windoze network settings and implementation. I don't want to go into detail. I offered such differences in settings as a possible culprit because you can't really assume that the Linux and Windoze drivers load the wireless card with exactly the same settings. Many wireless cards get most of their functionality from software, not firmware. If it were all in the firmware, I might suggest the two operating systems were identical. However, they're not, and you should not make that assumption even if he's using NDISWRAPPER. Each operating system has to be tested and configured individually.
I do it for amusement. You were also not under any obligation to provide sufficient information to identify the source of the problem. We can continue to discuss procedural and theoretical issues if you prefer.
Could I trouble you to ask him the question exactly as I asked. I would like to know if a different service provider works differently. I have no interest in his regular habits. Again, let me point out that you are making a fairly bad assumption.
Actually they do. I've often been mystified at the large changes in indicated signal strength between different versions of Windoze drivers. Intel 2200BG Proset drivers drove me nuts with this problem for quite a while. In addition, they also juggled the firmware, which added to the confusion. The problem is that drivers sometimes estimate signal strength using the packet error rate instead of the actual signal level. That results in some rather bizarre indicated signal strengths. I really don't know if the difference is that drastic between Linux and Windoze as I've never needed to check. Again, it would a bad assumption to assume that the card parameters are identical in both Linux and Windoze.
You're also assuming that whatever driver is installed, works well with whatever access point is being used in France. Wi-Fi compatibility is fairly good, but there have been occasional problems. I don't recall the exact hardware, but I've seen access point where only a few wireless clients can successfully connect. This is usually a timing issue between the access point and wireless client and often solved with a firmware or driver update. If there is a huge packet loss or timing issue, the ping test should show it.
He should see consistent 2-5 msec ping times to the gateway router. Any larger delays indicates packet loss and/or retransmissions. That could be poor signal strength in either direction, but can also be interference. Make sure he runs ping for a few minutes as the default 4 pings will not show much.
I hadn't heard that one, but it's possible. I don't know of any wireless provider that offers intrusion detection services for their clients. They may scan their own ports but not those of their clients. To do so would simply take far too long and generate far too much traffic. It also would need to be initiated from the gateway router as such probes would not be effective through a hotel firewall/router unless the hotel offers routeable IP's to it's wireless clients. However improbable, using the Windoze and Linux firewall in a possibly hostile location might be a good idea. I would be less worried about attacks from the internet, than from other users on the wireless LAN.
Reply to
Jeff Liebermann

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