Re: Weird Packet

[Justin Shore <macdaddy () NEO PITTSTATE EDU>]

On 2/20/01 3:25 PM Russell Fulton said...

> On Tue, 20 Feb 2001 10:53:33 -0500 Leon Rosenstein
> <l_rosenstein () MONTELSHOW COM> wrote:
>
> > Hi everyone.  I got this one packet last night (it was picked up by
> > zonealarm) and I was wondering if I might call on the talented people on
> > this list to help me learn how it was possible that the packet was on the
> > internet in the first place.
> >
> > The firewall has blocked Internet access to your computer (NetBIOS Name)
> > from 10.1.1.205 (NetBIOS Name).
> >
> > Time: 2/19/2001 21:51:48
> >
> > How is it possible to have that non-routable IP send a packet my system?
>
> We see these all the time, sigh... ISPs who use these addresses
> internally *should* filter so they never escape to the net at large, it
> would appear that some don't (or don't do it effectively).  If the
> packet gets out then it will be delivered to its destination address.

Another thought is that these aren't malicous in intent.  I get these all
day long on my firewall at my home (cable) from private addresses.  In
most of the cases it's someone's Windows box also on cable with me and
their personal firewall (if they're using one) isn't filtering that out.
Occasionally when I traceroute out through my firewall (firewall has a
public IP), I'll see a 10 one hop out (I don't use 10 personally).  Must
be my provider, but I'm not sure why.  interesting...

Justin


--
Justin Shore, ES                Pittsburg State University
Network & Systems Manager       Kelce 157Q
Office of Information Systems   Pittsburg, KS 66762
Voice: (620) 235-4606           Fax: (620) 235-4545
http://www.pittstate.edu/ois/

Warning:  This message has been quadruple Rot13'ed for your protection.