Router trouble: WLAN connection but no Internet

[eji]

About a week ago I got a DrayTek Vigor 2910VG router. The thing's a dream in terms of features (VoIP, Dual WAN, USB port, etc.), but WLAN has been a complete headache.

After a fresh restart of my iMac (see my sig for the computers on my home network, all of which are affected by this problem), I can usually connect to the WPA/WPA2-encrypted WLAN. Then, for reasons I can't determine, I will lose all access to the Internet and to other computers on the local network.

Yet during these dropouts I am still connected to the WLAN. Pinging the router at 192.168.1.1 is sometimes possible, though the response times vary from 1ms to 100+ms and I'm rarely able to access the router's config page. Another curious thing is that the AirPort signal level in the menubar appears to drop to, say, one or two bars, but it will fluctuate.

Reconnecting to the WLAN by turning AirPort off and on again does not work. Going to sleep and then reconnecting to the WLAN on wake does not work. I have to do a full restart of my computer, whether it's my iMac or my wife's MBP. Though that method doesn't always work either -- sometimes it takes two restarts.

The network can stay up all night with torrents running, or it can drop out in as few as five minutes after a restart.

As I was typing this, I got hit with another dropout. The only apps running are Safari, Mail, and Vienna, and mine was the only computer connected to the WLAN. I also freshly restarted my iMac and the router about ten minutes ago.

In hunting around for causes, I find a lot of messages like these in my Console logs:

Client application bug: DNSServiceResolve(XXXXX._udp.local.) active for over two minutes. This places considerable burden on the network.
Client application bug: DNSServiceResolve(iMac._afpovertcp._tcp.local.) active for over two minutes. This places considerable burden on the network.

... but none of them appear directly before the dropouts.

What I have done so far:

- Deleted all other previous AirPort entries in Sys Prefs > AirPort > Advanced
- Turned off IPv6
- Run Onyx (to remove caches, etc.)
- Created a new Network location with just an AirPort connection
- Upgraded the router firmware to the latest version (3.1.3) and reset it to factory settings multiple times
- Entered OpenDNS settings into my router (and later deleted them)
- Read this thread (Apple discussions) and this thread (MR) to no avail

Another odd thing is that sometimes just going to the Network field in Sys Prefs can cause the connection to drop. I thought it was just a fluke, but it's happened more than once.

I've had D-Link DI-524 and Speedport W 701V routers in the past year, but I never had this kind of connectivity problem.

Has anyone experienced anything like this? Can anyone help or offer any troubleshooting advice? Is it Leopard? My router? My wife and I both work from home, and with such flaky Wi-Fi connectivity, we're spending more time troubleshooting and restarting than working.

 

[Celeron]

I don't know if this is related to your problem but I was having similar problems with my mother's macbook. Sometimes it would connect, sometimes not. In either case the airport icon showed it was connected, however, when it wasn't working I couldn't ping anything. I've tried various things.

The last thing I've tried is changing the wireless encryption from just AES to just TKIP. This seems to have worked, however, it has only been a couple days so I can't say for sure. Even running AES and TKIP at the same time didn't work, I had to limit it to just TKIP. Maybe give that a try?

 

[eji]

I've tried is changing the wireless encryption from just AES to just TKIP.

I've tried unencrypted, WEP, and WPA/2, and I get the dropouts regardless.

My most recent experiment involves running iStumbler after I've experienced a dropout. Amazingly (or not, I don't know), running this tool sometimes allows me to re-establish an Internet connection and load some Web pages -- even though the signal appears weak. As soon as I quit iStumbler, I'm back to not being able to load any websites or connect to the outside world.

I thought that, since iStumbler allowed me to retain Web access, the problem be something as simple as interference. So I went out and bought a 10dbi antenna for a huge signal boost. Didn't help.

 

[Celeron]

Have you tried changing wireless channels?

 

[eji]

Yeah, I've run through the lot. I should have put the basic Wi-Fi troubleshooting steps I took in my giant list as well: changing channels, moving the router, with/without encryption, that sort of thing.

It's really odd. Yesterday evening I was getting signal drops every twenty minutes. I left it up running before going to bed and the signal stayed throughout the night. Seems like interference, no? But then if I were to turn AirPort off and try to reconnect right this very moment, I wouldn't be able to.

 

[eji]

Fixed!

In case anyone else has this problem:

DrayTek sent me release candidate (RC) firmware two days ago for the Vigor 2910VG. It solves all the wireless problems I'd been having with Leopard, and now my entire home network is using this router for the first time since I bought it six (or more) months ago.

So let it be known that, yes, while Leopard may have wireless bugs, these were solved by a firmware fix for my router. Which means the problems don't and didn't necessarily lie with Apple.

I've uploaded the file here for anyone else who might need it. But a few warnings:

- This is only for the Vigor 2910 series and has only been personally tested on my Vigor 2910VG.
- There may be even newer firmware by the time you read this post. In which case, check DrayTek.com.
- I accept no responsibility -- none, nada, zilch, zero -- if something goes wrong during or after the upgrade. The file that I've uploaded is the exact same one that DrayTek sent me, but your network or usage may result in a different outcome to the positive one I had.

Having said that, this is like manna from heaven to all frustrated DrayTek users.