IMHO this is a poor hint because even if you use DHCP you can specify DNS servers.

the OS may be trying to contact the router rather than the DNS server of the ISP.

It's the DHCP response from the router is what tells the OS what to use. Until that response is received the Mac will actually have no DNS settings and any DNS lookups will fail. Also, if you override the DHCP settings with static addresses then you'll need to change those settings any time you connect via a different network.

In most cases the address given will be its own address, and the router will contain a DNS proxy which forwards the requests to the ISPs upstream DNS servers.

nb: most routers don't proxy DNS over TCP, they only to UDP. This means that extra large DNS responses which get truncated can't be returned.

I have been having this problem on my Mac Pro for a few weeks. I am also connected via wired connection on this one computer. After updating to 10.5.4 and the firmware on my Airport Extreme, I was hoping the issue would be resolved. It was not, so I decided this workaround was at least worth a try. It did not work for me :( The problem is definitely the Airport router - I connected directly from my Mac Pro to the cable modem a couple of days ago for a few hours and experienced no connection drops. I also reset the router, which did not fix the problem. I am getting ready to just buy another router since the firmware update released this week did not address this issue and the connection drops are becoming problematic.

The first thing to determine when you're getting connection drop is if the problem is a problem with your wireless connection or with the wall connection.

Since you've got an AEBS and a Mac Pro, try setting your network to 802.11n in the 5ghz spectrum (click the option key when you select the network type). All kinds of weird things can disrupt 2.4ghz signals, including such innocuous things like dehumidifiers.

I wouldn't go buying a new router just yet. I have a similar problem, and I'm running a linksys router with dd-wrt firmware, and the two macs that use it have the same problem. Ironically, when I boot my Macbook in Windows mode, there's never an issue.

There is another setting, that may be causing this behaivor, namely MTU. I noticed a lot of drops when the MTU was set to 1500 and I was using the router from my ISP. Setting it a bit lower on the MacBook did the trick (1460 was the max for my setup).

The logic doesn't make sense to me, but if Rob doesn't have the problem and uses static DHCP, it might be worth a shot. The weird part for me about that problem is that when my computer is booted in Windows mode, it's fine.

Using static IP or DHCP has nothing to do with this.

- The ISP provides DNS addresses to the router, assuming the usual dynamic-IP ISP connection. (If you buy a static-IP connection, you're told what DNS addresses to configure into the router.)

- If the computer uses DHCP, the router passes those DNS addresses to the computer.

- If the computer uses static IP, the computer can simply forward all lookups to the router/gateway address. If you've entered some DNS addresses, the computer uses them.

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EMOJO: mojo no longer workin'

This certainly sounds like the trouble I'm having at my girlfriend's place. She can connect without hassle to her wireless network on her Vista laptop, but my MacBook just won't load any webpages (but has great connection bars and the WEP is correct etc.).

Under the DNS bit the only numbers listed are the address of the router AND it is greyed out.

I am beyond frustrated with it. I guess I will try this when I'm next round.

It sounds like the issue is inside the router. Either it's not receiving DNS info from the ISP, or its firmware is wrong.

I have seen that Earthlink DNS (at least in my area) isn't providing DNS addresses to the router. As a result, the router doesn't work properly. I either enter DNS addresses into the router or the computer(s).

Why not simply use standard DHCP and enter opendns.org addresses in the network settings? This works perfectly all the time. Those DNS servers are 208.67.222.222 and 208.67.220.220.

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EMOJO: mojo no longer workin'

I switched to manually using these DNS servers a long time ago because of connection issues and huge delays accessing various web sites. It's worked great for me.

Typo: "find it's way" --> "find its way"

I've been using an AEBS g basestation for a while now and only started having these problems when Leopard was released. I have roommates that are on Windows and Tiger and also have a Tiger machine myself and the only time I have this problem are using my Air or my work Macbook Pro, both on Leopard.

Wireless networking in Leopard has been nothing but trouble. I've tried many different configurations on my router, even though I know it's not the router, and I've yet to come up with a viable solution. If I could downgrade my Air to Tiger I would.

Possible fixes:

Set your Renew DHCP Lease to either very frequent (that once helped my connection stay alive) ... or very infrequently.

Input OpenDNS servers in Network panel ...

AppleTalk gets turned on with some archive & installs / upgrades; make sure that's turned off. Check your other network settings too, just in case proxy's on by mistake.

MacPilot by Koingo has a number of options for presets, depending on your connection, that it will temporarily or permanently apply. Must be fifty for cable modem - not fair to them to copy here, of course, but you might want to take a look.

This isn't a keychain issue, is it? They can be stubborn - worth deleting relevant entries and starting fresh by letting the system ask you, Remember this in Keychain? Which is sometimes the only reliable way.

And keep resetting that ABS - I've got an Airport Express that can take 4 or 5 resets after a system upgrade now, but once it remembers, no drop outs.

My wife gets this problem on her Black Macbook (2.0GHz Core Duo). The AirPort signal indicator will very briefly drop and then come back. This ONLY happens when the MB is NOT connected to the mains power. When it is connected to the mains power there are no signal drop outs. Tried just about everything I can think of but can't fix it. I think it's a hardware issue because of the difference when using the power adaptor. These are the steps i've tried:

Boot from my MBP using target disk mode and FW cable, still the same - this rules out any software error
Re-set PRAM, PMU

I'm using a Netgear router provided by my ISP, haven't tried another yet.

Anyone have any other ideas? I guess last resort is pay for someone to service it.

I'm still having those dropouts with Ethernet connexion to my ISP's box with router mode enabled.

I've tried DHCP, DHCP with specific DNS (OpenDNS and others public DNS), Static IP, change MTU to 1450... Nothing works !

The only way to instant recover connexion is to unplug Ethernet and plug it back. VERY annoying !!!

Here's how things are for me:

1. Since leopard I used to only have problems initially getting on the wireless network from sleep, but now it's started dropping out randomly in the middle of usage after 10.5.3-10.5.4 on my MBP.

2. In the Network Diagnostics tool, more often than not it's stuck at the ISP green light; the Internet and Server lights are both red. When I get to selecting the airport network I want to join, often (but not always) it asks me to put in a password for the network, even though I don't have it secured (used to, that didn't help, either!). Eventually by turning Airport on and off, it starts working again.

3. I don't see why it's the router. I've been having endless problems since Leopard with a linksys router that had been working perfectly before, and works fine now for some computers (but not mine).

3. I'd been using the Open DNS servers before Leopard, that sure doesn't seem to be helping.

4. I'm not sure what MTU is--where is that in the network prefs, or is it in the router?


Thanks!

here's a mystery - 3 MacBooks sharing a connection with latest APX 'n' series.

Internet runs sweet as for eMac via ethernet cable and MacBook #1 via Airport - but as soon as another MBook connects, MB #1 loses connection - as will MB #3 if it comes on.

meantime MB #1 and eMac surf away happily - only solution for the other 2 MBooks is to connect via an ethernet cable.

this has only occurred since upgrading APX from 'g' to 'n'

there is one particular MacBook that seems to have precedence over the others - could it be in its settings??

any clues???

I just reported this problem the Apple and their fix was to change the channel selection of the Airport from Automatic to a number. They told me to set mine to 9 but I think that should be a random number.

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Binary Bear