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When I power up my modem, home network and machines, sometimes the machines don't connect to the internet. Why would this be happening? Is there anything I can do to intervene?

(See my setup below)

The order I usually choose for power up is:

  1. Switch on Modem and Bridge1 (both on same extension power block sockets). Modem boots
  2. Not waiting for modem to finish booting (all 5 lights green) I switch on Bridge2
  3. And straight after that I power up all three machines
  4. Once All powered up I then can see if they are on the internet or not (if not, the yellow warning hazard triangle symbol shows over the connection symbol)
  5. Then I may power up my NAS (which I think is irrelevant in this problem but included for completeness).

Details on hardware:

  • Bridges are a 4 port Zyxel 1Gb ethernet
  • Modem is Thompson speedtouch 580 ADSL with 4 x 100Mb/s ports and WiFi. Occasionally I have a HTC Desire Z phone and iPod touch connect to it, also a Revo Pico Radiostation internet radio. (But I feel their roles are irrelevant in this problem, here for completeness)

Update 2

Added printer, again for completeness, don't think it causes the issue.


Spare room:                                    Lounge room:   

                                    +---+      +---+        +-------+
Windows 7 32bit home--1Gbs----------+ B |      | B +-100Mbs-+ Modem +-----> DSL line
                                    | r |      | r |        +-------+
MacBookPro (inc.Bootcamp w7Pro)-1Gbs+ i +-1Gbs-+ i |               +------+
                                    | d |      | d +-1Gbs----------+ NAS  +
Toshiba NB100 XPHome--100Mbit/s-----+ g |      | g |    +--------+ +------+
                                    | e |      | e +100Mbs settop|
Epson SX600FW print/scanner--100mbs-+ 2 +      + 1 +    +--------+
                                    +---+      +---+

      ((( HTC Desire Z ))) via wireless (occasionally)

      ((( iPod touch ))) via wireless (occasionally)

      ((( Revo Pico RadioStation internet radio ))) via wireless 

share|improve this question
Do you mean Zyxel? And also Why bridges? Why not a simple 1GB switch? Also you failed to mention what type of setup you have DNS/static ips/DHCP/etc; is the modem serving ips/dns gateway? etc? – Jakub Apr 12 '12 at 14:29
Usually the modem has some sort of log accessible through its web interface: does it say anything when you get those errors? – Renan Apr 12 '12 at 14:35
+1 @Jakub yes Zyxel (I will correct). The bridges were cost effective (approx 20 pounds each). It also meant I only needed to run one gigabit cable between rooms rather than three. But perhaps I have cut corners as you might be indicating? The setup is DHCP for the devices (when I go into admin of speedtouch.lan I see that). As for IPS/DNS gateway I would have to check... But the setup should be fairly typical for a home ADSL modem with ethernet and wifi ports I would think. – therobyouknow Apr 12 '12 at 14:41
+1 @Renan I did look at the logs and it did say once about the NB100 PC name having an unresolvable address. But I haven't been too scientific about it to date, so perhaps I should be - I haven't been recording the logs meticulously everytime the problem is encountered. I would say at least 66% of the time, it's been OK. What I can't understand is why it 'decides' to not work on some days. After all this is digital equipment 0 or 1, don't have bad days. – therobyouknow Apr 12 '12 at 14:44
@therobyouknow, when you experience limited connectivity, are you able to ping ips on the network? Or is your IP not even assigned to your interface? – Jakub Apr 12 '12 at 14:46
up vote 1 down vote accepted

With incomplete information I'd put my money on a DHCP issue. Turn the Modem and two bridges on and let the modem finish booting before turning anything else on. (The DHCP server not being available during a reboot should not be an issue for Windows 7 so it's probably an issue with the modem/router).

share|improve this answer
+1 @BJ292 yes, I would prefer that being the problem, the SpeedTouch 580 ADSL is a rather old modem (6 years+) so the firmware may not cope with some scenarios. What do you think of the setup - a suggestion elsewhere on here is that bridges might not be suitable and perhaps instead a switch. I would consider a change of hardware if I knew it would bring more certainty. I think at least one other device as well as the modem will be necessary as most cost effective home modems I've seen offer 100Mbit ports given that internet doesn't come close. But for faster sharing locally,a 1Gbit LAN suits. – therobyouknow Apr 12 '12 at 18:04
I'm a great believer in sweating the assets so if changing your boot sequence solves the problem I'd live with it. If I was buying new kit I'd get an ADSL modem/router with a built in 4 port Gb switch for the lounge and get a basic 4 port Gb switch for the spare room. – BJ292 Apr 12 '12 at 20:17
+1 @BJ292 for "sweating the assets" - I agree as I too prefer to make the best of what I have rather than resort to forking out cash. I started out with the 580 ADSL router with 100mbit ports. Then I decided I wanted a 1Gbit LAN as most of my computing devices supported it including my NAS and I wasn't benefitting from the reliability and speed compared to wireless. I did look for 1Gbit ADSL modem routers but they seem rare, most are 100mbit. – therobyouknow Apr 12 '12 at 22:19
One further question, do you know if ADSL routers remember how they fulfilled DHCP requests last time they were on? (I don't mean the configuration) but rather, like, who and how they allocated IP addresses last time they were switched on. I ask because a few days ago my setup did not work at all - no internet, no matter how many times I restarted and tried different sequences. It seemed like the modem was remembering to misbehave and storing some bad behaviour in flash perhaps. – therobyouknow Apr 12 '12 at 22:22
I don't think your issue is with DSL attenuation. It's probably a timing issue somewhere in your setup. Are you rebooting or powering off and on. Also your ISP will do a training cycle when your speedtouch connects to provide optimum connection speed - possibly it caches these setting across quick reboots which speeds things up - possibly making your speedtouch available fractionally earlier for DHCP requests etc. You could confirm this by booting the speedtouch first and not turning anything else on until it has a solid connection. – BJ292 May 1 '12 at 13:16

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