Situation:
You have Norton Internet Security (NIS) or Norton Personal Firewall (NPF) 2003 installed. You get an Intrusion Alert from your Internet Service Provider every few minutes that looks similar to the following:

Details: Intrusion: Invalid IP Options
Intruder: xx.xx.xx.xx
Risk Level: Medium
Source IP address: xx.xx.xxx.x
Destination IP address: 224.0.0.1
Protocol: IGMP.
Invalid IP Option: 0x81f6b358.

Solution:
Symantec is investigating this problem. The cause is unknown, and there is no solution at this time. This document will be updated when new information becomes available or a solution is found.

Workaround
To stop the Intrusion Alert screen from appearing, exclude the Invalid IP Options signature from Intrusion Detection. Excluding Invalid IP Options will not disable the firewall. Your computer is still protected when connected to the Internet.

NOTE: Exclude the Invalid IP Options signature only if necessary.

To exclude Invalid IP Options signature:

1. Open NIS or NPF.
2. Click Status & Settings in the left pane.
3. Double-click Intrusion Detection in the right pane.
   
   NOTES:
   • This only applies to NIS 2003 users.
   • You must have NIS Supervisor rights to exclude the Invalid IP Options signature. If the buttons in the Intrusion Detection screen are disabled (greyed out), then you do not have NIS Supervisor rights. Contact your System Administrator to continue with these steps.
     
     
     
4. The Intrusion Detection screen appears. Click Signatures.
   
   
   
5. In the Signatures: box (left window), navigate the list and click "Invalid IP Options" so it is highlighted.
   
   
   
6. Click Exclude. The "Invalid IP Options" signature disappears in the Signatures: box and appears in the "Excluded Signatures:" box (right window).
   
   
   
7. Click OK.