# XP: TX/RX light on DSL modem always flashing **URL:** \ **Category:** Factual Questions\ **Created:** [December 27, 2003, 11:42pm UTC](https://boards.straightdope.com/t/xp-tx-rx-light-on-dsl-modem-always-flashing/221327 "2003-12-27T23:42:49Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![akrako1](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@akrako1](https://boards.straightdope.com/u/akrako1)\ **Post date:** [December 29, 2003, 8:07pm UTC](https://boards.straightdope.com/t/xp-tx-rx-light-on-dsl-modem-always-flashing/221327/21 "2003-12-29T20:07:20Z")
I have broadband internet access via cable, no DSL, but I have noticed something similar. The light on my cable modem is nearly constantly blinking, even if my computer is sitting idle. One day, I installed a router in-between the cable modem and my computer. Guess what happened? The modem light continued to blink, but when looking on the router, the PC activity light was not blinking, but the router link activity light was blinking. The router has a built in firewall, and I have it set to it’s lowest security setting. What I’ve surmised this to mean is that the broadband network is causing the activity, not my computer making calls out. Possibly handshaking, pinging, or other network protocols running - anyone know specifically? Also, cable, and I believe DSL modems, have their firmware occasionally updated from your service provider - which will activate the activity light. Try running a decent firwall with logging, and you can take a look at all the traffic yourself. I would also highly recommend running adaware and sbybot-seach and destroy - at least to remove any other possibilities. ---
**Author:** ![YourOldBuddy](https://avatars.discourse-cdn.com/v4/letter/y/bc79bd/32.png) [@YourOldBuddy](https://boards.straightdope.com/u/YourOldBuddy)\ **Post date:** [December 29, 2003, 10:51pm UTC](https://boards.straightdope.com/t/xp-tx-rx-light-on-dsl-modem-always-flashing/221327/22 "2003-12-29T22:51:49Z")
U guys need to run antivirus programs and spy detection progams like adaware or spybot. ---
**Author:** ![Declan](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Declan](https://boards.straightdope.com/u/Declan)\ **Post date:** [December 29, 2003, 11:56pm UTC](https://boards.straightdope.com/t/xp-tx-rx-light-on-dsl-modem-always-flashing/221327/23 "2003-12-29T23:56:40Z")
> [@](#): > > \*Originally posted by scott evil \* > \*\*When I got last month’s bill from my ISP, I noticed I was charged for “extra usage”. This has never happened before. The difference in my PC is that I intalled XP last month. > > Since then, I’ve noticed that while connected - even when idle - the TX/RX light on my DSL modem is always flashing. It goes particularly mental when I’m connected from my user account and then my other half switches to his user account. > > So, something is polling the modem, and I’m paying for it. It has to be related to the fact that I’m now using XP. How do I make it stop? \*\* Did sympatico send you a log dump to show you that you have been using more traffic than you are allotted. I was under the impression that Sympatico dropped that two tiered billing system. Declan ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [December 30, 2003, 2:33am UTC](https://boards.straightdope.com/t/xp-tx-rx-light-on-dsl-modem-always-flashing/221327/24 "2003-12-30T02:33:33Z")
Ignoring all this MS stuff… you said the light’s activities seem to correspond to actions on your computer. This would seem to strengthen the [spy|spam|ad]ware theory. Though your broadband connection is certainly being probed by dozens of script-kiddies, trojans, worms, etc. every minute (my firewall is set to drop most incoming traffic, but I can still see the RX light blink waaay faster than it did just a few years ago), that activity would be unrelated to the state of your PC. Could be spamware (spyware that sends spam for somebody), or someone using your box for IRC stuff, or perhaps your machine has been recruited as a zombie for attacking other machines. Check with your ISP. I recently used a uh… substantial amount of bandwidth and got knocked for it; they probably have a page where you can check incoming/outgoing traffic. If it’s all incoming, then someone’s trying to DOS your machine (unlikely) or something else is screwed up. More likely, it’s mostly outgoing, sending spam or attacking people. As for what to do, I’d recommend Spybot… perhaps run “netstat” on the command line and see what’s using the network too. Asking your ISP for help might be useful. They might check what port traffic is on to categorize large useage as filesharing, spamming, etc. [Previous page](https://boards.straightdope.com/t/xp-tx-rx-light-on-dsl-modem-always-flashing/221327.md?page=1)