Strange ICMP activity happening on the firewall

[Maybay]

I have a laptop and i access net every single day. Also i am the only single user of my system no one else use's it. I observed a a strange problem. the problem is that i have observed that ICMP requests emerging into the my firewall wan port and i traced it going somewhere to a china manufacturing mobile device. I found it really strange. As i specified earlier that there are no other users who use my system, still its happening. So i want to know why are these china mobile manufacturer's trying to communicate with my system. So i am trying to find the reason behind it, so that i get the detailed result of whats happening. So please do help me with these strange problem. Following are the details that i can give
ICMP Destination Unreachable, Code: 3

[Wguy2008]

Looking at the code which specifies that code is 3 and the destination is unreachable. Looking at that i can say that it is not the ICMP request but it is the ICMP error response. Now this error response can only be generated when the request arrives at a port and there is nothing there to list it. So the udp port sends back with the message saying that the destination unreachable. So this can be a situation where your system may be sending such blank requests have a check with your system and if possible don't allow such type of udp connections in the firewall.

[BiGMaCHiNe]

Well if you ask me these udp ports send such type of error message only when there is no request contained in the port. There can be several situation which may have arise. One such situation can be someone from the particular manufacturing company is trying to access the udp port of your system and your system may be replying it with the message saying that there is nothing available here. This is happening because your firewall is allowing such udp ports to enter your system. So don't allow such connections to happen from the firewall.

[HiSpeed]

There can be various such scenarios arising out of this. You have specified that you are the lone user of the system and no one else access it, fine agreed but there are various such connections that are trying to connect with your system and gaining information of your system from their place and you may be having no idea whats going on. One such good e.g. of this is packet sniffer. However looking at your situation the people you have traced are the china mobile manufacturer's. Those people can be trying to port scan your firewall and configure them in such a way that they allow unsolicited UDP or they are trying to gain some important information from the system and your server is down due to some bad reason. There can also be a possibility of some one from your internal network generating the error message and is giving the source of the china mobile manufacturer's. Situations are endless but you have to be careful for your system's safety.