[Zoom]

In the last few weeks, I've had a very troubling problem with my PowerMac G5: many times (80% ?) when it wakes up from sleep, it can't connect to the internet. I have to reboot it. I leave my Mac on all the time. I also leave my MacBook Pro on, but it doesn't have this problem. I have other internet devices, too (Vonage, etc) that can access the internet just fine - it's only my PM and it just started happening in the last few weeks.

Anyone else seen this? Is there a simpler way to kick it than rebooting? I've tried renewing my DHCP license, which appears to work, but doesn't fix the problem.

[ghporter]

Does it really take a reboot? Have you tried doing something else other than rebooting and renewing the DHCP lease? Also, is this connection by cable or AirPort? This distinction is pretty important, because sometimes AirPort cards don't quite "get it" that the computer has been asleep. The fix is to manually disconnect and reconnect via the gadget in the top menu bar. It seems to be related to a few issues that sort of work together against you, and it's usually something that happens because of a firmware update to the AirPort card-and goes away with another one, eventually.

[Zoom]

Yes, it takes a full reboot, which is painful. Logging out and back in doesn't even do it, I don't think - I may try that method again. It's hardwired - GigE. Actually, it's GigE locally, which is connected back to a 100Mb wifi router, then to the cable modem. But everything else on the little GigE switch can get to the internet. I'm not sure what's going on.

I've had some trouble with iChat on and off, too, for a long time. Sometimes video works, sometimes it doesn't. I'm having a very hard time tracking it down (see other posts by me on this). I'm starting to think it might be this same computer.

Could it be the NIC on this Mac is getting flaky? It's not consistent, which makes it maddeningly hard to debug.

What else can I try?

I just triggered a memory on this... I think I tried poking around with traceroute and such... there seemed to be an issue with DNS lookup. I'll have to try that again next time it happens. I just got home now, my PM was asleep, but when I woke it up and logged in, I had internet service.

[ghporter]

Traceroute will tell you hop-by-hop where you're connecting and where you aren't. Once you know that, you can concentrate on fixing where the connection stops. But if it's DNS, traceroute won't help you at all. If it's a DNS issue, I'd search for free DNS services and manually plug those in-probablly to both the router and the client. There's a possibility that your Power Mac refreshes its DNS addresses differently and/or on a different schedule than the MBP simply because of the different network card.

[Zoom]

I'm wondering if this isn't a function of my network somehow. Let me get that out here, just in case.

cable modem
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NetGear WGR614v6 (wifi router)
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NetGear GS605v2 GigE switch
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PM G5 (and others)

I have a couple things hanging off the wifi router, too (Vonage, Xbox). I had said that my MacBook Pro was hanging off this GigE switch, too, but actually it's hanging off a Cisco ECT (hardware VPN) box, which is hanging on the GigE switch - so the DNS problem wouldn't affect it.

I have one other computer off this GigE switch. Next time I have this issue, I'll have to see if it's affected as well. Note that laptops using wifi don't seem to be affected.

These problems may have started happening when I introduced the GigE switch. Could it be related? Not sure on that, though.

[Zoom]

Okay, it's definitely a DNS problem. I just lost it while my Mac was wide awake. I had saved off some public IP addresses a few days ago in anticipation of this moment. I pinged them and got responses. But I can't ping them by hostname.

I added two public DNS servers under my built-in Ethernet settings and applied them, but it's still failing. Do I need to restart my Mac for these to take effect?

The DNS servers edit box was empty, but obviously it was working before. If I recall, the DHCP server is supposed to pass those along from the service provider, right? Are they shown anywhere in the Mac Network prefs? If I put in my own DNS servers, will these be in addition to those or am I replacing those?

[update] Wow... that's weird. This posting came BEFORE the one with the network layout, but it's showing up as posting at a time one hour from now (in the future)....

[ghporter]

Some server somewhere between you and MacNN seems to have realized late that the U.S. changed from Daylight Savings Time over the weekend...

Give Google a try with "free DNS". If you manually set DNS servers (you can use free servers or look up your ISP's servers and use them), that should mend-but not really "fix"-the problem.

[Zoom]

So, has this problem been seen before? I haven't gotten any hits on Google for this problem. Where is the likely culprit? Is it the NIC on my Mac? Is it my Wifi router? Cable modem? I guess the better question might be: in my network topology, who's responsible for DNS?

I actually wasn't aware that DNS stuff expired. Maybe I'll have to do some digging into the specs....

[ghporter]

DNS doesn't expire. But your ISP's DNS servers may change-and they don't always keep the information that goes to the customers as up to date as they should. And sometimes stuff just happens and your settings get goofed up.

[Zoom]

Well, adding the extra free/public DNS servers didn't help - it just happened again. I can't figure out what the trigger is. I didn't have the eMac running, so I'm not sure if it's happening there or not. I've fired it up now though - we'll see if it has the same problem.

This is VERY annoying. I wish I could find some other way to get it working without having to restart. Logging out and in doesn't do it. What else could I try? Renewing my DHCP license doesn't help, either.

[Zoom]

Apparently it's just the one Mac that has this problem. My other Mac (eMac) doesn't lose its DNS.