This is from my ZoneAlarm;
""Details
ICMP messages are the Internet's control messages. Routers and computers use these messages to determine how to route information from one place to another on the Internet and to keep track of the routing of that traffic. The ICMP Destination Unreachable message tells your computer that something you tried to send could not be delivered to its destination. An additional code within the message indicates the reason. Some examples of reasons why your data might not be deliverable include:
No route currently exists to reach the network you were trying to reach.
No route currently exists to get to the specific computer you were trying to reach.
The packet of data that you were trying to send was too large.
A network administrator has installed a packet filter that refuses to forward the kind of communication you were trying to send.
The reason code in the message that generated this alert was 0. Please see the links below for detailed information about different ICMP Type 3 Destination Unreachable codes and their meanings.
Internet standards dictate that the ICMP Destination Unreachable messages is only sent as a response; however, hackers frequently disregard these standards when trying to attack or break into other people's computers. For this reason, if ZoneAlarm detects one of these messages and cannot determine what it is responding to, ZoneAlarm will block the message -- for example, if the response took too long, or if the packet is not a response at all.
The action of blocking the message normally has no effect on your application if the message was legitimate. It does however protect you against hackers if the message was not legitimate.""
I haven't sent anything at all today, and nothing has tried to access the Internet (well, not through ZoneAlarm anyway!) ... so, is this a hack attempt?
The number it gave was 213.121.143.83
Boy, am I glad I've got ZoneAlarm...and use it! ;-)
Deli