Confirmation of AirPort Extreme failure on certain sites

Originally posted September 14th, 2004

Yesterday we reported a problem where certain websites cause AirPort Extreme base stations to fail completely, i.e. no machines using the base station are able to access network services. We are seeking additional confirmation for the issue.

We've since received several notes confirming this issue, as well as some additional details on what might be causing the problem.

MacFixIt reader Tom writes:

"Not only does Safari kill the Airport Extreme Base Station when attempting to load certain web sites, it kills my Macsense wired router when I am not using wireless at all. If you look at the Activity (under the Window menu in Safari), this occurs when the JavaScript tries to load a ShockWave item that cannot be found. After about a minute, the router will come back. I expect the bug is the same as for the Airport Station getting a WAN IP from the DHCP server. I have experienced this particularly on eBay auction pages that call files on various servers--the router loses its WAN IP address and requires 60-90 seconds to get another."

It should be noted that a number of other readers cite some eBay pages as triggering this issue.

Reader Dennis Murphy adds:

"I've confirmed that the web page listed here: http://homepage.mac.com/brossow/macfixit/safari_aebs_crash_page.htm stops any outbound traffic through my Airport Extreme Base Station.

"I've used Safari to access that page from my Power Mac G5 (first gen, 2x2.0) as well as my 15" Aluminum Powerbook, and both times, I had to reset the AEBS.

"It seems to me that the AEBS resets itself (it disappears from the Airport Admin Utility), but once it came back, I had to login and do a 'Reset' from the 'Base Station' menu to get any outbound traffic to work.

Mark Issacs-Ward corroborates:

"I've had an Airport Extreme network for over a year now. The same symptoms described happen to me, too. And it happens on various sites! The one thing they all seem to have in common is a java implementation. I too have several Macs and one WinTel machine on the network. All computers are connected via 54 megabyte/sec cards to an Airport Extreme Base. When the problem occurs, only a full shutdown and restart of the Base Station will get it back online again. Even machines that are plugged into my ethernet hub via hardwired connection (and are pulling IP addresses from the DHCP Server in the Airport) are affected.

"When I access certain web sites, the Airport Extreme just locks up. It takes a reboot to get it going again. I've applied every patch Apple has released (both to the Operating System Software and those that are Airport specific) and the same thing continues. I cannot believe that Apple is unaware of the problem. I've written them several times about the issue over the past year. And yet to receive anything other than an automated response... typical of Apple these days."

Problems also reported with AirPort Express Though we've yet to experience such a phenomenon with our in-house AirPort Express, a handful of readers report network connectivity drops similar to the aforementioned with the device.

One reader writes "I do have similar, intermittent 'crashes' where one or more computers lose access to the AirPort Express entirely. I too am using it in DHCP/NAT mode connected to a 3mbps cable modem. When it happens the computer that gets dropped has its signal strength meter go to zero and it can no longer see the base station with airport admin utility. Sometimes the other computers will continue to network just fine, but once one is dropped, it cannot get back on without restarting the base station. Most often though it drops them all at once. I have a network throughput app running on the G5 and I notice that while downloading I can have a steady rate for hours and then all of a sudden the throughput drops very low for a few seconds and then stops completely. The latter coinciding with the disappearance of signal strength."

What is causing the problem MacFixIt reader Darrell Kienzle may have found the root cause of this issue, opening the door for some workarounds:

"I ran tcpdump while loading the site that causes the crash, and it looks like Internet Explorer only makes a single DNS query for the site against the AirPort Extreme Base Station. But Safari hammers the AirPort Extreme Base Station with one DNS lookup for every single little linked element on the page. So the AirPort Extreme Base Station is getting a huge number of DNS requests before even the first response gets back to it from its upstream DNS server. And I think it's just killing the DNS service on the AirPort Extreme Base Station."

So one workaround, based on Kienzle's findings, might be to set up a separate DNS service that alleviates the AirPort Extreme of that duty.

We're conducting further testing and will pass along any new details that emerge.

Resources