I'm trying to diagnose a rather odd networking problem and am a little stuck on how to progress further on the diagnosis.

The network in question uses a D-Link DSL-G604T router. Everything works fine, often for a day or two. Then, suddenly, wireless clients no longer have Internet connectivity. The clients can be Windows or Linux - it makes no matter. Restarting the clients does not help. Restarting the router fixes the problem.

In addition, the clients can still connect to the router. If I log onto the router admin page, I can successfully ping external sites. Therefore, the router itself still has a connection to the Internet.

I've checked the router logs at the time of the drop-outs and there is nothing of note. I've also upgraded the router to the latest firmware, but that did not resolve the issue.

Can anyone offer any tips on how to progress with this?

  • Manufacturer support or is it old? – Coops Dec 30 '11 at 10:22
  • Quite old. Was hoping for a quick & easy fix since it's my parent's router and I'm only in their country for another week. – Kent Boogaart Dec 30 '11 at 10:59

Hm not a promising review on Cnet;

The Good:no connection issues for 2 years

The Bad:constantly drops out every few hours

worked fine for 2 years n now i get constant dropouts every few hours.. also sucks if u have 2 xbox's, never get open NAT on both xbox's

I did a bit of research which may help you;

http://forums.whirlpool.net.au/archive/621651 - Good advice here;

Also check all your line filters - a bad one can cause poor speeds and/or dropouts (not droppings - those are caused by birds).


exact setup as mine...change modulation to d.gmt this should solve all your problems, you will however find you cannot sync higher than about 8mbs on g.dmt, if you want higher change to G624T firmware, from this thread forum-replies.cfm?t=603357


NB to change modulation go go to in browser and got to advanced tab and scroll down to adsl tab


drop outs on a computer are not internet drop outs, so dont change the modulation type, just call dlink and do a firmware upgrade to fix the wireless drop outs.

as i mentioned i have EXACTLY the same setup as he does, right down to the wireless card and i WAS experiencing WLAN dropouts, but not internet dropouts and changing modulation to g.dmt fixed all my problems, apparently theres a fault with multimode and wireless on G604T


Dump it and buy Netgear box instead. It will cost you more than 70 in time to get this one woroking OK unless you either a) Turn ALL security off or b) Use only D-link wireless cards


I was having the same problems for months.

It transpired that the BT cables in my house were not digital. A BT engineer had to come out and replace all the cables.

Problem solved.

http://www.the-scream.co.uk/forums/t25469.html - Could need an engineer to come out if still no joy;

BT came out today, did something at the telegraph pole that had had the DACS, and it's working fine this evening.

Tesco's customer service throughout has largely consisted of the same routine questions being repeated at my expense - had I reset, restarted, unplugged everything else, tried the test socket - followed by suggestions verging on ridiculous. Once I had confirmed the obvious internal connections and setup had been checked, they should have had a record of what I had already done. I wonder if this is representative of most broadband suppliers.

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  • I personally love Netgear routers but they aren't too cheap and I have also has good experience in the past with D-Link so it may just be this model unless it is a problem with your (BT or other carrier) line – Coops Dec 30 '11 at 14:19
  • Tried changing the modulation but just had another dropout. – Kent Boogaart Jan 1 '12 at 6:27
  • As others have said it maybe it is time for a replacement, most broadband providers will provide a router for free if you they don't want to buy another – Coops Jan 3 '12 at 11:31

I'm assuming this is your D-Link?

enter image description here

There are two options that immediately present themselves:

First, update the firmware

Update your firmware to the latest version for your model. Go to Dlink.com, select your country, choose your model and then find the firmware download. For example, in the USA, this is the page for the G604T.

Make sure to follow the instructions, since you shouldn't update the firmware over the wireless connection. It should be a relatively simple process though.

Second, script a scheduled reboot

The G604T has a telnet interface to a BusyBox shell. You could make a simple script that connects to the G604T and performs a reboot. Then, schedule it on someone's computer on the network using Windows Task Scheduler or crontab depending on the OS. Perhaps have it run every night at midnight if there is a computer on the LAN that is on 24-hours or have the script run at the logon of a user. Tailor it to the use of the network so that whatever is most likely to happen once a day will trigger the script.

An example of a Telnet script

The list of commands that can be run will be found on the BusyBox site here and not within any D-Link manual for the modem/router.

For information on scripting a Telnet connection, there is the StackOverflow thread "Creating a script for a Telnet session?" and an article titled "Telnet Scripting for the DSL-G604T". Here's an example from the latter article concerning Telnet scripting: 23
WAIT "login:"
SEND "root\m"
WAIT "Password:"
SEND "admin\m"
WAIT "#"
SEND "help\m"
WAIT "#"


  1. Update the firmware.
  2. Reboot the modem on a daily schedule

Unfortunately, I am accustomed to having to do this kind of thing, especially with consumer grade networking equipment running DD-WRT.

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You have done everything possible software-wise, so the problem seems to be either hardware or environmental.

Nothing lasts forever, including routers. I would suggest buying a new one from a shop that does refunds, so that if it also fails then you could return it for a refund.

However, if the new router also fails, then this might be an environmental problem, such as a strong magnetic field or radiation. (Your parents haven't for example bought a new microwave oven and placed it by any chance right next to the router ?)

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  • Alas, no microwave near the router. However, it used to be my router about 4 years ago and I never had any issues with it at all, so probably is environmental. Was hesitant to buy them a new router because I have a gut feeling it will suffer the same problems. Hmmm, will check prices. – Kent Boogaart Jan 2 '12 at 23:24

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