Having trouble getting my Macbook to communicate with other devices on my network.

September 20, 2011 7:46 PM

I'm having trouble getting my Macbook to reliably communicate with, well, anything else on my network, and not having a spare router or laptop is not helping the troubleshooting process.

First off, I'm a professional software developer, also with a few years of helpdesk support under my belt. This is not to imply that I know everything - ye gods, far from it - but I mention it to indicate that I'm a bit beyond the "turn it off and on again" category.

Now then: I've got a Macbook (early 2008 model). I've also got an Xbox 360, an AppleTV, and a Medialink wireless router. I used to have a secondhand Time Capsule for my router, and then it died; before that I had a string of Belkin, D-Link, and Netgear routers. I've gone through so many because A) I've until semi-recently had roommates/parents who brought their own, and B) I appear to have particularly good luck with my computers, in that I've never had a hard drive death or other hardware failure, but awful luck in routers, in that they regularly just... stop working after a year or two. The 360 and the ATV are jacked straight into the router via Ethernet, and always have been.

Now, only in this brave new Medialink world have I had a desire to have the Macbook talk to anything else on the network. So I don't know whether to blame this problem on the router, or the laptop. I don't have a second computer I can test with, nor do I have a spare router to swap out (and apparently nobody else I know does, either.)

The problem is: Whenever I try to get anything to communicate with the laptop, it only works about 1/3 of the time. This includes:

* The laptop detecting, and being able to stream audio to via iTunes, the AppleTV
* The AppleTV being able to pick up the laptop's iTunes library as a source
* The Xbox being able to pick up the copy of Connect360 I run on the laptop, as a pre-ATV get-my-videos-into-my-TV solution
* Things on my iPhone being able to sync with Things on the Mac, which is a LAN-based process.
* The Apple Remote app on my iPhone can see the AppleTV just fine, but not the laptop.

Streaming stuff across the LAN sometimes works, but often doesn't, and when it does, the 360/ATV will often lose access after, say, half an hour, and then I'll be unable to get it working again within that troubleshooting session (ie, I may try again a couple of days later, but just messing around for a while, I don't get it back). It doesn't necessarily work right away after a reboot of either the laptop or the Other Gadget.

At no point in this process does the laptop show any errors, problems, etc, and its network access appears uninterrupted; certainly, internet access via the router works fine. In fact, right as I post this, iTunes refuses to see the AppleTV (and vice-versa) even though it was working this afternoon. Until i started trying to throw data around the network, I never had any problems at all with the laptop, ever. It is, of course, out of AppleCare at this point.

The problem's been present on Leopard, Snow Leopard, and now Lion.

I've dug around the MediaLink router's settings for anything that looked useful, but its menus are impressively useless; everything's either a vague checkbox without explanation ("Prevent Network Attack") or not something I've heard of before ("Reverse Direction Grant, "MCS Auto").

The wireless network is setup as a mixed 802.11n/g, though previously it was g-only. There aren't many wifi networks in the area, and I haven't had problems with reception in general in the past. It helps, of course, that the laptop is about ten feet from the router.

Attempting to google this has been unsuccessful, in part because there's no error message, and most people encountering similar problems seem to never be able to connect devices, because of misconfiguration or some other blocker - this intermittency of this is what's driving me nuts and making it hard to research.

So, uh... any ideas?

posted by Tomorrowful to computers & internet (11 answers total)

Do you have the latest Lion update? There were some network stability fixes in there which have helped me significantly.

Other than that, it could be either your router or your laptop, however I find this unusual "It doesn't necessarily work right away after a reboot of either the laptop or the Other Gadget." What about rebooting the router, have you tried that? If it works after a router reboot, it's your router.
posted by zemaj at 7:58 PM on September 20, 2011

Thanks for all the info.

You seem to have enough connected to warrant a boot order.

Shut everything off. Unplug everything.

Wait 30 seconds.

Restart the router with nothing plugged in to it.

Start up the laptop. Make sure it gets an IP from the router.

Plug in and start the other items one at a time. Make sure they get IPs.

You should be able to see each individual item on the network via your router's config screen. Make sure two items aren't trying to get the same IP.

I hope that works. Good luck.
posted by Sphinx at 8:10 PM on September 20, 2011

You wouldn't happen to have a cordless phone around, would you?
posted by mhoye at 8:32 PM on September 20, 2011

Can you ping the other devices when this happens?
Can you ping the router when this happens?
posted by Threeway Handshake at 8:46 PM on September 20, 2011

What might help us to troubleshoot is if you can tell us how each thing is connected (e.g. cabled or wireless).

Guessing a bit here, but... assuming everything is wired except the laptop & iPhone, I'd start to suspect Bonjour discovery / Multicast DNS not being routed properly between the wired & wireless subnets. Does everything work OK if the laptop is connected by ethernet rather than wireless?

If it is that, you'll probably have to open up the firewall in your router to 224.0.0.251:5353 to allow it to cross between the wired & wireless subnets (if it even can - I've had trouble with Belkins particularly before, so now I just recommend people buy Airports ;-)
posted by Pinback at 8:56 PM on September 20, 2011

imo. with that much apple stuff, get an airport, then call apple to have them help you fix it.

Does it happen when you aren't using wireless on the laptop?
posted by empath at 10:02 PM on September 20, 2011

Most consumer routers simply bridge the wireless and LAN Ethernet ports, and don't give you any way to shape or control traffic between those. All the routing, shaping and firewall stuff they offer is between the LAN and WAN sides. So unless you've got a gross wireless connectivity fault I'm thinking it isn't your router.

I have seen Macs fail in very weird ways when configured to acquire their IP addresses from non-Apple DHCP servers on wireless networks. So one thing you might care to try is setting up your laptop with static IP, DNS and gateway addresses and see if things improve.
posted by flabdablet at 5:20 AM on September 21, 2011

I have a spare wireless router you can borrow if that would help in your testing, I believe it is this one. I work in Philly.
posted by 8dot3 at 5:54 AM on September 21, 2011

"Most consumer routers simply bridge the wireless and LAN Ethernet ports, and don't give you any way to shape or control traffic between those. All the routing, shaping and firewall stuff they offer is between the LAN and WAN sides."

My experience differs; probably more than half put the wired and wireless sides on different subnets (granted, they may be in the same class C), and on about half of those the firewall also works between the two subnets (granted, that may not be deliberate ;-)

That said, I don't see a lot of consumer-grade crap these days. But the symptoms the OP relates - particularly the "works for a while at first, then drops out, only randomly recovers after reboots, while normal connections continue to work fine"-ness of it - have a lot in common with Bonjour / mDNS not being passed.

"I have seen Macs fail in very weird ways when configured to acquire their IP addresses from non-Apple DHCP servers on wireless networks."

I personally haven't seen that, except in the case of extremely crap DHCP servers (e.g. dnsmasq - though, to be fair, I only played with older versions before giving up on it as a piece of shit; it may be better now.). Much more common is the opposite - client devices failing to get an IP address from bootpd (which, at least pre-Leopard, handled DHCP as well) when OS X is used as the DHCP server. That's because it too was (is still?) a piece of shit ;-)
posted by Pinback at 4:46 PM on September 21, 2011

Doesn't sound like you've done much in the way of isolating your problem in order to test what's happening.

For example, jacking the laptop straight into the router, then pinging other devices and seeing if your services run correctly. Then running the same test wirelessly. Perhaps run a service you know is going to crash the network the way you have it now, try that on a jacked connection to see if it runs right.

Really your problem is finding a common denominator where everything works correctly, then scale upwards a step at a time to the scenario you want to be at, pinging devices and watching for disconnects and other errors.

When I diagnose network errors, I usually have the network utility app open and pinging the router nonstop while I do other things and see what happens. That's a good basic test of connectivity. If you are pinging through, yet connections fail, then perhaps it's not just the network failing. If the pings are intermittent, then yes, there's a network issue.

Just on the face of it, I would start wondering about some basic network compatibilities between the MacBook and the router on the wireless protocol you are using that's causing things to fail. Have you tried changing wireless channels for instance? Perhaps also change from n to g wireless signal.

Anyway, you should be starting from a jacked connection, confirming your setups are working correctly, the LAN is stable and services work, then go back to wireless, using the ping tool at every step to watch for outages.

Good luck.
posted by diode at 9:17 PM on September 21, 2011 [1 favorite]

Diode: You're right, I really hadn't done a proper isolation. Shame on me; minus five geek points.

Other than that, it could be either your router or your laptop, however I find this unusual "It doesn't necessarily work right away after a reboot of either the laptop or the Other Gadget." What about rebooting the router, have you tried that? If it works after a router reboot, it's your router.

You know, I did this in the past - but it would always break quickly, so I didn't think of it as "fixing" the problem. You're right, though - it does work immediately after a router reboot, consistently, even though it does stop working shortly afterward.

Result: Grabbed a new D-Link router, plugged it in, jacked into it, and no problems in the 24h since, including listening to full albums of music.
posted by Tomorrowful at 12:33 PM on September 23, 2011