Hi

It has been asked - somehow : What is your LAN setup? It looks like you have one
machine acting as "gateway" for the other boxes.
Then, it is explainable that you receive 137 attempts from outside on that machine.
I also bet, the source was one machine within the subnet of your ISP you are in.

Otherwise: Configure your router properly, which means in short:
Disallow any incoming traffic except for servers possibly running within your network.


What is a request on [UDP] 137? (as mentioned in your post, disregarding the title)

This might be a WINS broadcast request, with high probability. WINS is an older way for
NetBIOS name resolution and is sent by default from a lot of Windows machines.
Often, it is nothing to worry about (but I have already proven in earlier posts that I am not
paranoid enough )

If it is incoming traffic on Port 139, then it might be some attempt, as mentioned by
nihil. First, make sure that such packages are dropped at your firewall, second, and
in any case, patch your machines.

Cheers