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Date:      Thu, 22 Feb 2001 02:27:20 -0500 (EST)
From:      "Michael Richards" <michael@fastmail.ca>
To:        cjclark@reflexnet.net
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re: Odd firewall messages
Message-ID:  <3A94BF58.000023.66147@frodo.searchcanada.ca>

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>> Anyone have any wisdom when it comes to decoding what I'm seeing
>> here?
>
> That is the NetBIOS garbage that WinXX machines chatter with. You
> redacted the destination IPs, were they broadcast addresses? Those
> are NetBIOS name resolution packets. They could be hostile, but by
> far the most probable scenario is someone with a misconfigured
> network is leaking them. You would not happen to be living off of
> a public broadcast domain?

These were not broadcast addresses. In fact, some of the IPs were not 
even used. I assumed it was some sort of scanning but was not able to 
figure out how they were getting answers. It seems odd that providers 
would not filter outgoing packets if they are coming from IPs that 
don't belong to the ISP. We are hooked up directly to the core router 
at our service provider. No public or broadcast happening with us.

The 137 seems to point to NetBIOS but there are others such as:
21/02/2001 10:54:22.184764 xl1 @0:6 b 10.3.0.146,1957 -> x.x.x.x,80 
PR tcp len 20 11264 -S IN
That are hitting the webserver of our busiest server.

I guess it's probably nothing to worry about.

-Michael
_________________________________________________________________
     http://fastmail.ca/ - Fast Free Web Email for Canadians
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