Wire why

[j4]

I wrote a long blog post on paper, and was looking forward to typing it up on a computer with a real keyboard, but got home to find that we had no internet access.

This may seem like a slightly odd thing for an internet addict to say, but: I hate home networking. I wouldn't hate it if it worked, of course -- if it was like electricity, working at the flick of a switch, no configuration required, total failure so rare that we're still talking about the last time it happened -- but it's never like that.

I'll freely admit that the real problem exists, as they say, between keyboard and chair. I don't understand most of the component layers of the problem, I don't really understand the way they interrelate, and as for understanding how to fix them when they go wrong -- hopeless.

My view of the setup is something like this: my laptop has a radio-thing in it that lets it talk to the Airport; the Airport is plugged into the router; the router is plugged into phone socket. So INTERNETS comes out of the phone socket, and the router speaks fluent internet, and interprets it for the Airport, which can shout loud enough for other stuff to hear it. Roughly. I can vaguely tell where the problem is (if the computer can get a wired connection directly via the router, then the Airport is probably the problem; if it can't, blame the router) but that's not a lot of help: if nothing has changed, why has one of these devices stopped working? Why does rebooting so frequently fix it? I feel like a superstitious idiot unplugging the magic white box and plugging it back in again, but 8 times out of 10 it fixes things. Sometimes unplugging doesn't work, but a 'hard reset' does; sometimes, power-cycling the router fixes everything. Sometimes, nothing works. Like today.

The other problem is that even if I really understood DNS, TCP/IP and so on [waves hands as if trying to unravel a large bundle of unidentified greyish wires], the INTERNETS would still be coming THROUGH THE PHONE SOCKET, and this part of the setup is a) magic and b) subject to the whim of BT and Eclipse. So any attempt to do the right things with the computer, Airport and router is constantly undermined by the fear that things are mysteriously Not Working outside the realm of Stuff I Control. It's not working... Have I got something wrong? It's working again... Is that because of what I did, or because Mr BT turned off the switch marked 'BOTLEY INTERNET FAIL'?

There's also the lurking worry that by buying a cheap router and a second-hand Airport I have doomed the whole project to failure. More superstition, probably: do the gods of internet require a costly sacrifice? But this is secondary to the real problem: too many components and not enough understanding.

So, rather than asking (as I have done previously on LJ) 'please to make mr understand internets', I will try to ask some more specific and practical (and probably dumb) questions:

1. How can I test the ADSL connection without using the possibly-rubbish router?

2. What could make a correctly-configured Airport/router suddenly stop working for no apparent reason? (If the answer is 'nothing' then my inference is that it's not correctly configured...)

3. If component A is intermittently malfunctioning, is it possible that rebooting component B could affect it? (If not, I fear I'm left with either loads of crazy coincidences or the increasing certainty that none of the components of this mess actually work reliably.)

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Comments

[crazyscot.livejournal.com]

1. Not much you can do short of trying another router. Alternatively, most (all?) routers have a web interface for config and diagnostics; it'll tell you about your line status and whether (for example) your line tripped out. Particularly if your line's usual ADSL speed has only a small noise margin, your line might be susceptible to tripping off and/or retraining from time to time - but this should be a quick thing, outage of only a minute or two.

2. Umm. Radio interference? Depends on the distance between mac and airport, whether there's anything nearby emitting junk radio noise, other folk using the same wifi channel, cosmic rays, power surges...

3. Very unlikely. Rebooting B and it starting working again is arguably indistinguishable from the case where you did nothing for a couple of minutes and then tried again to see if A had spontaneously come back to life.

[crouchinglynx.livejournal.com]

1. How can I test the ADSL connection without using the possibly-rubbish router?

By having a spare router (or just an ADSL modem) - preferably from a completely different manufacturer, so that any bugs or misbehaviours aren't likely to manifest on both at the same time - and having previously set it up and confirmed that it works. Then if suddenly, neither of your routers work, there's a good chance it's your ISP or BT that are to blame. This may be a slightly expensive option, but as the second router is a backup, it doesn't have to have all the features of the main one.


2. What could make a correctly-configured Airport/router suddenly stop working for no apparent reason?

(This is where I have to find a point somewhere between technical and condescending.)

Bugs in the firmware, usually. Some oversight that is triggered by a rare, but not impossible, sequence of events, leading to the program getting itself in a knot, and either freezing completely, or working much less effectively than normal. Rebooting fixes it because the program gets to start again from scratch, completely forgetting about whatever mess it had previously encountered.

Check the manufacturer's website for firmware updates (and then see if they also have some support forums where other users have whinged about how the new firmware's worse than the old one).

3. If component A is intermittently malfunctioning, is it possible that rebooting component B could affect it?

It's possible - if component B's startup routine involves communicating with component A, then getting component B to do all its startup routines again could lead to it sending A some data that causes A to break (eg. due to circumstances described in the answer to question 2) while the previous time round it caught A at a different time, or sent a slightly different sequence, that didn't trigger the bug.

But with no knowledge of what A and B are, I'd think it more likely to be a coincidence. I'm assuming there's nothing in the manual like "make sure you've switched on A, plugged in all the cables and counted to ten before switching on B" that would imply such a connection?

[hairyears.livejournal.com]

Typing HTTP://192.168.0.0 or HTTP://192.168.1.1 will probably call up a configuration page for your router. The password's always admin.



Wireless routers and 'Airport' devices have some interesting failure modes... Among them, overheating components, which fail when the device has worked for 10-20 minutes.

[(Anonymous)]

やっぱり、本部にいくほうがいいね。

[sesquipedality.livejournal.com]

I've never owned or used a wireless router that wasn't flaky as all hell. I believe the technology is fundamentally flawed. Now I'm using power line ethernet and very much happier, although it's not so good for laptops, I admit.

[emperor]

Our Airport hangs off a Real Computer that does all the Complicated Stuff, and we have no problems with it.

Your ADSL router probably has a web-configuration interface (and a telnet one, but...); if you talk to that when the internets go away, you'll find whether it thinks it has ADSL-happyness or not.

Sometimes traceroute (your mac has it, in all likelihood) can help - if it finshes somewhere in your ISP, then it's probably their fault...

My ISP will lend you an ADSL router for free, and also has web status pages telling you when it thinks your line is up/down/fish.

[pir.livejournal.com]

The older linksys wireless routers I used were ok (went months without problems, buthad to choose channels carefully) but my current favourite is my airport extreme gigabit; 802.11N run on 5GHz and never had a single problem, never had to reboot it, never had interference and over 10Mb/sec throughput with ssh... but then I only use wireless for laptops.

Pretty much all other consumer grade gear I've used has sucked.

[katstevens.livejournal.com]

I'm afraid the only helpful advice I've gleaned from years of interweb woez is to make sure that the company supplying your broadband hasn't changed your password without telling you.

[pir.livejournal.com]

1) As others have said; look at the admin interface to see if it's hung/borked or if the line is unhappy. If it claims to be connected ok then traceroute (I prefer mtr, but you'd have to install it) can tell you how far your connection is getting. It may not be a problem on your end at all, but this is where you can get more information about that.

2) Overheating (make sure all devices and their wall warts have decent air-flow and are in a fairly cool place), external interference, bugs (if packet type X arrives right after packet types Y, D and Q... hung airport). Make sure the firmware is up to date (via the airport utility on da mac), try changing the channel manually (only 1, 6 and 11 are worth using). iStumbler on the Mac can tell you what other channels things are using in your area, use the least used one.

3) Unlikely but possible. If one device is wedged then rebooting a directly connected device could free it up... but yeah, rather unlikely.


Be methodical. My usual routine when something goes down is to check the computer is getting an IP, traceroute/mtr to www.google.com or similar and see how far it gets (if it fails, traceroute to an IP to see if DNS is failing). If it fails inside my network, try wired net. If it never gets ouside the house, check the router's information. If that doesn't respond, powercycle it.

[addedentry.livejournal.com]

2. A cordless phone?

[addedentry.livejournal.com]

Thank you! Eclipse have suggested overheating as a contributory factor; I was sceptical. Unplugging the router to cool down was sometimes effective but unfortunately indistinguishable from rebooting.

[scat0324.livejournal.com]

I agree with this post.

(although make sure you get the right headquarters)

[strange-powers.livejournal.com]

I've got a cheapo Belkin wireless router/modem (cost about £45 three years ago) that has never gone down, and supports two wireless laptops, one wired laptop, and wireless Xbox 360, Wii, DS and iPod touch daily.

The technology does work.

[pjc50.livejournal.com]

1) As others have suggested, this needs the use of a different router.

2) Last time I moved house I threw away two wireless routers, on each of which the wireless part had stopped working while the router still worked. Not sure exactly what happened but probably overheating killed the radio module.

3) Yes. Networking is particularly prone to this sort of thing. Trivial example: if you plug a cable from a router back into the same router, or otherwise make a loop in your network, the entire network will probably stop working.

[crazyscot.livejournal.com]

Vaguely possible, but unlikely; I thought they used different frequencies. (Wifi 2.4GHz or 5GHz; DECT cordless phones 1.9GHz; old cordless phones down in the two-digit MHz. However if there's foreign gear of questionable legality involved, who knows?)

[sparrowsion]

Another vote for 2: overheating. I've got a no-name switch connected to the wireless router which occasionally fails, taking out the wired portion of the network. But only ever in hot weather. Fortunately, it's easy to diagnose this condition (the connected port lights are exactly wrong).

[sbp.livejournal.com]

The other thing you could do is get an external antenna with a higher gain (from e.g. Maplin) and plug it in to your wireless box. This along with a channel change to a less used channel helped my set up work better.

NB I don't use an Apple Airport so I don't know if you can fit an external antenna.

[lnr]

We've got a wireless router and the wireless is all absolutely fine. We're now using it with wires, because we can actually get close enough for that, and we're having more trouble than before: because we've moved house and it's the actually ADSL connectivity that's buggered, not the wirelessness.

I had bloody awful connectivity for a couple of hours on Tuesday afternoon: it kept cutting out and then only coming back for a few minutes, if that, before cutting out again. It's definitely the line in our case. If it starts doing it more often I think I'll have to call our ISP, but it's mostly OK.

[hoiho.livejournal.com]

Bluetooth & microwave ovens also use the 2.4GHz band (only 801.11A uses 5GHz, and that's not licenced for Europe)), as do some model aircraft remote controls.

All, except microwave ovens, use frequency-hopping, so shouldn't block a WiFi signal to the degree that it stops working entirely. And a microwave shouldn't normally interfere unless it's either close, large, or leaky.

[ewx.livejournal.com]

My favourite networking bug:

Ascend Pipeline 50 ISDN routers were configured by default to proxy-arp for all addresses they thought were on the internet side, presumably to save you having to enter a router address into all the local clients. (DHCP-capable clients might not have been ubiquitous at that point.)

Unfortunately this meant that if you plugged it into a physical network with hosts that disagreed with the P50 about what IP network they were on, for instance if you plugged it into the office network while configuring it for a customer's intended settings, it would use ARP to advertise itself as the right target for all your local IP addresses. Any host that was slower than the P50 would therefore become inaccessible as everything tried to send all the traffic for it to the P50 instead.

Our Windows boxes crashed in short order when this happened! Turn off or unplug the P50, e.g. because you'd finished setting it up, and everything started behaving again, at least until the next one. Took us quite a few before we realized what was going on.

[sesquipedality.livejournal.com]

Do you have it configured securely (ie using WPA-PSK, hidden SSID)? Do you have other wireless devices that share the same spectrum (DECT phones, bluetooth, wireless mice and speakers)? If both of these things are true and you still get signal without dropouts, then I'll believe it works.

At least for you. It's never worked for me.

[strange-powers.livejournal.com]

I have very little security - MAC filtering and hidden SSID is enough for where I live and for what I use. If I were running a business it would be different, certainly. As for other wireless devices... I've got a cordless phone, bluetooth controllers, wireless mice, digisenders etc but have no idea whether they're on the same spectrum or not.

Either way, it works for me as it's supposed to and never drops... so it works.