Repeated intruder alert

  Simmpy 19:59 20 Apr 05

Norton Firewall keeps informing me of an intrusion alert. It describes the intruder as and the intrusion as "Invalid Source IP Address" If you click OK it comes up again instantly, after about 5 to 6 repeats of this it goes away until the next time you open the internet. What can I do to stop this? It describes it as a low risk?

  Klof Ron 20:03 20 Apr 05

It's just letting you know it's doing it's job. Turn off alerts if it bothers you.

  octal 20:07 20 Apr 05

Its not an intrusion, its broadcast traffic, its necessary, its probably your ISP asking "who is there and what is your address" without that traffic the internet wouldn't work. It happens every few milliseconds if you monitor it.

This is what's buzzing away in the background on my connection: click here

  GANDALF <|:-)> 20:43 20 Apr 05

The 'alerts/attacks' are merely computers on the net asking your computer if it is still connected; these queries are called 'handshakes'. When you are connected to the net you could be going through many servers and routers. This occurs in a millisecond, so you do not notice. All these routers and servers need to know that your computer is receiving, so that they can send images and WebPages to your IP, which is in effect, your mailbox or receiving station. When on the Net you can pass through more than 20 servers and routers and they could all be handshaking your computer at short intervals. You will notice many of the 'alerts' come from Telecoms, which should come as no surprise as they own most of the routers etc. It is also interesting and miraculous that the 'alerts' disappear when you pay for the *ahem* Pro-Version of a firewall (see Zonealarm;-) ).


  VoG II 20:46 20 Apr 05

Agree with the above but I find that is odd - I thought this was a netmask not a real IP address.

Turn off the alerts anyway.

  octal 21:09 20 Apr 05

This is a bit simplistic, but it gives the idea, scroll down towards the bottom for broadcast: click here

  VoG II 21:12 20 Apr 05

Thanks. Always learning...

  canard 22:57 20 Apr 05

I used to get a lot of the 255s and I blocked them with the firewall. Everything went on working. I don't get 255s now because, I suspect, that my ISP has at last started blocking them.

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