Packets from 255.255.255.255(80) (was: Packet from port 80 with spoofed microsoft.com ip)

From: Tomasz Papszun (tomek-incidat_private)
Date: Thu Jan 30 2003 - 10:03:51 PST

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    On Thu, 30 Jan 2003 at 14:31:36 +1100, Keith Owens wrote:
    > On Wed, 29 Jan 2003 21:46:53 +1100, 
    > Michael Rowe <mroweat_private> wrote:
    > >I received a packet on my cable modem today, allegedly from
    > >microsoft.com: 
    > >
    > >18:41:35.663374 207.46.249.190.80 > my.cable.modem.ip.1681: S866282571:866282571(0) ack 268566529 win 16384 <mss 1460>
    > 
    > I am seeing a lot of sync/ack packets from port 80 to non-existent
    > addresses on my networks.  Somebody is spoofing source addresses to
    > attack hosts, we are just innocent victims.  When will ISPs learn that
    > they should filter their customer's packets to prevent spoofing?  I am
    > even seeing syn/ack packets from 255.255.255.255:80!
    > 
    
    Similarly at my networks.
    Yesterday evening (Jan 29 21:10 GMT+1) a very noticeable stream of such
    packets started to come into my networks.
    
    All are TCP, from 255.255.255.255(80), destined to various random
    addresses (even not used) to various port numbers.
    
    This appearance is very noticeable. Before yesterday, single packets
    from 255.255.255.255 were coming in rate about one for three weeks.
    Since yesterday there have been about 1680 for 22 hours.
    
    -- 
     Tomasz Papszun   SysAdm @ TP S.A. Lodz, Poland  | And it's only
     tomekat_private   http://www.lodz.tpsa.pl/   | ones and zeros.
    
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