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Why Do We Have To Restart Routers?

jaypaulw writes "I've owned a WRT54G, some cheap D-Link home Wi-Fi/firewall/routers, and now an Apple Airport Extreme (100/10 ethernet ports). In the context of the discussion about the worst uses of Windows — installation in places where an embedded device is superior — I've gotten to wondering why it's necessary to reboot these devices so frequently, like every few days. It seems like routers, purpose-built with an embedded OS, should be the most stable devices on my network."

22 of 936 comments (clear)

  1. The most likely reason by Anonymous Coward · · Score: 5, Funny

    You're doing it wrong.

    1. Re:The most likely reason by pablomme · · Score: 5, Funny

      Yeah, I've never had a problem with my rou

      --
      The state you are in while your HEAD is detached... - wait, what?
    2. Re:The most likely reason by Anonymous Coward · · Score: 5, Funny

      Mine never used to need re-booting until I added a Vista Laptop to the network???

    3. Re:The most likely reason by livewire98801 · · Score: 5, Informative

      I'm a network admin for an ISP, and we've been recommending UPSs for the frequent-reboot routers that our customers have. We've found that routers (especially Linksys) have a real problem with power fluctuations that most other systems and devices don't notice. A decent line-conditioning UPS might solve your problems, but a cheap one will suffice.

      Also, could be the device is running out of memory, if your ISP is changing the properties of your connection a lot, or you might have a duplex issue causing a lot of retransmissions. . .

      Just a couple of thoughts :)

      --
      "He may be mad, but there's method in his madness. [...] It's what drives men mad, being methodical." G.K.Chesterton
    4. Re:The most likely reason by nuintari · · Score: 5, Interesting

      mod parent up, as I came here to say that.

      Also, the Linksys WRT54G up to version 4 was a fine router, plenty of memory, ran Linux, was very stable. Then Linksys decided that quality wasn't nearly as important as driving me batshit insane, and we started getting tons of complaints about users needing to reboot Linksys routers, which came _highly_ recommended from the geek squad over at worst buy.

      The modern WRT54G, and anything past version 4, that doesn't have an 'L' in the name is an utter piece of crap, firmware revisions to the VXworks OS they now run have helped, but they are still lockup city.

      --

      --Nuintari

      slashdot : where an opinion can be wrong.

    5. Re:The most likely reason by PitaBred · · Score: 5, Insightful

      DD-WRT on my WRT54GL, I've never had to reboot it for those issues. I even have a couple separate VLAN's set up, two DHCP pools on separate interfaces, etc. I've had uptimes of over 80 days before I tweaked something else on it that required me to reboot it.

      It's not the hardware... it's the generic crap software that they run on.

    6. Re:The most likely reason by pablomme · · Score: 5, Funny

      Oh, very simple: I have a fr

      --
      The state you are in while your HEAD is detached... - wait, what?
    7. Re:The most likely reason by DamnStupidElf · · Score: 5, Informative

      In theory, none of those routers should need a UPS, just a better AC-DC converter perhaps with a bigger capacitor across the DC lines. I've never investigated the quality of the wall warts they supply with routers, but my guess is they are very cheap and simply don't handle voltage fluctuations as well as they should.

    8. Re:The most likely reason by Cylix · · Score: 5, Informative

      The problem I've had with dd-wrt and torrents is the max tcp connections is by default very low. Not something you would notice under normal traffic, but during swarms it can fill up fairly quickly.

      It give the appearance the unit has locked up since it is difficult to establish a tcp connection. These will bleed away eventually and allow a connection to be established.

      I just set the max number of tcp ports and it fairs fairly well using bit torrent now.

      --
      "You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
    9. Re:The most likely reason by Plutonite · · Score: 5, Funny

      Yeah, I've never had a problem with my rou

      You know what, those jokes are fucking la

    10. Re:The most likely reason by Achromatic1978 · · Score: 5, Informative

      Most often, actually, I've found that the cause is, gasp, Bittorrent. Fills up the NAT tables and they're not purged fast enough, unable to open / map more ports, effectively, no more connectivity.

    11. Re:The most likely reason by Flossymike · · Score: 5, Informative

      This MS KB may help.

      http://support.microsoft.com/kb/932134

      There is also an MS KB related to the broadcast flag which may be what is being referred to.

      http://support.microsoft.com/kb/928233

  2. USR8054 by NFN_NLN · · Score: 5, Funny

    US Robotics 8054 (USR8054). At least it has the decency to reset itself though throughout the day. Saves some manual labor I suppose.

  3. Because they are cheap by Anonymous Coward · · Score: 5, Insightful

    Fast, Stable, Cheap - pick two.

  4. TCP Timeout by allanw · · Score: 5, Informative

    TCP connection timeouts on some routers default to 3600 seconds or one hour. So, when you use some Bittorrent or such, opening lots of connections, your router keeps these connections (even after disconnection) in its memory for up to an hour. It fills up and your router grinds to a halt, opening connections very slowly.

    There's other timeouts too, but I'm not sure exactly what they do. Firmware like HyperWRT lets you change these timeouts to something much shorter, like 90 seconds, which typically prevents lock-ups like that.

    (I'm actually not 100% sure that this is the sole cause for router lock-ups)

  5. I never have to by missing000 · · Score: 5, Informative

    Not to be a dick, but I use a wrt54g with tomato firmware and it's about the most stable and powerful (QOS is great on it) router anywhere close to the consumer price range.

    I never have to restart my DSL router or Vonage router either, and I've kept all this stuff up 24/7 often with heavy use for years at a time.

    If you're restarting networking stuff all the time, perhaps you've misconfigured it...

  6. The problem is.. by Fjornir · · Score: 5, Insightful

    ...the expectations of the user. Newsflash: when you buy cheap crap it is going to perform like cheap crap.

    --
    I want a new world. I think this one is broken.
  7. Re:Buy one that works. by 7+digits · · Score: 5, Informative

    So you are lucky. My Airport Express needs to be rebooted from time to time (nothing damning, the express sometime stands month without needing it). My previous UFO Apple Airport also needed to be rebooted (and much more frequently than the Express).

    The symptom on the Express are that DNS queries stop working. I can ping it, ping my DSL modem, and ping website for which I have IP. I can nslookup into my provider DNS. I cannot lookup into the Express DNS.

    Another issue is that sometimes, I start getting more and more lag. Rebooting the mac or the DSL model doesn't fix it. But I discovered, amazed, that rebooting the express fixed it.

    Btw "Buy one that works" is an extremely arrogant comment. Those units work for you, it does not prove it works for anyone else.

  8. Re:My theory... by AimHere2000 · · Score: 5, Informative

    I base this on absolutely nothing, but my primary suspect is the cheapskate power supplies that these devices come with. However I've never cared enough to test it out.

    I think you're right. This seems to be especially common on D-Link routers. I used to run a DI-624 which was stable for years, until one day it just started rebooting itself. Did it infrequently at first, but progressed to the point where it rebooted continuously and was unuseable. Poking around, I discovered that the AC adapter (power brick) was not only VERY warm, the plastic shell was actually deformed a little on one side. I replaced the AC adapter, and the router worked good as new... until a few years later, when AGAIN it started rebooting, then stopped working entirely. And AGAIN, the AC adapter was at fault (totally dead this time). And again, replacing the AC adapter resurrected the DI-624.

    It seems to me that the manufacturers of residential-class routers really skimp on the power supply, or at least D-Link does. The AC adapters they've bundled in recent years are smaller than a deck of cards, yet I'm supposed to believe that they can put out 3 amps of current at 5VDC indefinitely?

  9. Re:embedded network devices by bwy · · Score: 5, Interesting

    Funny, I think everyone here has had to reboot their router to solve problems in the past. But, in typical slashdot fashion, 99.9 percent of the posts are people telling the author of the question that he is stupid, lacks intellectual ability, must be a high school drop out, or has some bastardized sexual persuasion that prevents his router from working.

    As you say, it could be an unrelated issue that resetting the state machine fixes. In this case though I guess I superior device could do this on its own.

  10. tcpip timeout, too many connections by po134 · · Score: 5, Informative

    it's simple, most router keep tcpip connections alive for 3600 sec or more (especially d-link one), so each time you establish a connection on a bittorrent client your router open a new one. After a few hours, sometimes a day or a few ones, it can become a problem very quickly as you might imagine. Just install dd-wrt or tomato and drop the timeout to 360sec, it'll do the job.

  11. I hope this explains a few things. by Sillygates · · Score: 5, Insightful
    --
    I fear the Y2038 bug