I am using master DNS with forwarders, Open DNS and Google name servers and DHCP on my PC; ADSL router is a relay.

My ADSL router (TD-8840T 2.0) has had some strange behavior during the last couple of weeks

After some amount of time (ranging from a few minutes to several hours), when I send a request to a web page (I mean any page like google.com) it loses ADSL (the LED switches off).

I am not sure, but I suspect it restarts.

After a minute or two LEDs come back and traffic continues until the next time the LEDs just go off.

I bought it from my ISP more than 3 years ago.

Wireshark is not showing any unknown traffic.

I can not find what's wrong.

Could it be that its lifetime is up?

I am using my PC 10h daily.


Called tech support of my ISP. They said to try it without phone and splitter, and it showed the same result.

SNR margin downstream is very low probably due to signal from national telephone agency and that if it restarts I should call them again with values from ADSL part of status panel.

enter image description here


I made another call to my ISP since router continues to restart.

Caught the restart values in the image below

  • SNR margin downstream is negative (-5.-1)?
  • CRC 2014

enter image description here

My tech support is telling me they will call the national telephone agency to check out the signal.

  • It almost sounds like the problems I sometimes have with my router. Mine is getting old (I’ve had it for 8 years), and sometimes it just won’t work. The strange thing is that it seems to be limited to web pages (HTTP). What kind of router do you have? Does it get hot? Can you still access other things like P2P? If the LEDs are actually going out, then it may simply be dying. If so, then try asking your ISP for another one. Also check eBay and local classified ads for a cheaper used one. – Synetech Aug 9 '13 at 2:06
  • What kind of router do you have? its TD-8840T tplink. Does it get hot? yes its hot, and no not hotter than usual it has been working for 3 years tho. Can you still access other thing? no, when leds are out ping google.com returns unkown host google.com – nkvnkv Aug 9 '13 at 2:25
  • It really sounds like it is dying. Unfortunately electronics just don’t last anymore (especially, tiny, complex electronics). Routers are known to fail after a few years, and if the LEDs are turning off, then you should see if you can find a replacement (at least see if you can borrow one just to test if the problem goes away). – Synetech Aug 9 '13 at 2:40

Problem solved: the signal was too weak, my ISP boosted the signal.

SNR margin downstream is now around 22dB.

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