Snort false positive

Hi list,

We have Snort 2.4.4 and in the logs appear a lot of Port Scan traffic of
this type:

(portscan) TCP Portsweep
(portscan) ICMP Sweep
(portscan) UDP Portsweep
(portscan) Open Port

And the payload of this alerts is like the above:

Payload (ASCII):
Priority Count: 5.Co
nnection Count: 4.IP
Count: 14.Scanned I
P Range: 192.168.1.9
:65.54.171.28.Port/
Proto Count: 8.Port/
Proto Range: 80:3410
.

This alerts come from a lot of our network computers but they seems to
be clean of spyware, worms, etc...

We need to know if this is a false posivite or we have a problem in our
LAN.

Tanks!
-- 

   Isidro CatalÃn Ramos
   Administrador de sistemas
  -----------------------
      Amigophone S.L.
   [ www.amigophone.es ]
  -----------------------
   Telf: +34 933 661 007
   Fax:  +34 933 661 012
   icatalan@amigophone.es



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