HELP!? SYN Floods and TCP FIN Scans

by geminimoon66 - 1/19/12 2:48 PM

Belkin N 150 Router - F6D4230-4 v2 (01) Using WPA-Personal
( PSK ) security.

Service provider is CT Communications with a 3 Mbps
download and 1 Mbps upload speeds.

We average 2.60 Mbps Download and 0.75 Upload and Ping is
30ms-40ms

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On the router we have:

<span style="mso-spacerun:yes"> 3 - Desktops that
are hardwired and all are using Win7, Avast A/V, Malwarebytes and Spyboy
S&D.

They are all clean and up to date.

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1 - Laptop using the WiFi with Win Vista, Avast A/V,
Malwarebytes and Spyboy S&D. Also clean and up to date.

1 - Laptop using the WiFi with Win7, Avast A/V,
Malwarebytes and Spyboy S&D. Also clean and up to date.

2 - <span style="mso-spacerun:yes"> Xbox 360 using
the WiFi

1 - <span style="mso-spacerun:yes"> Roku Box using
the WiFi

1 - <span style="mso-spacerun:yes"> PS3 using the
WiFi

<o:p> </o:p>

There are times when the Ping jumps to 1000ms - 1200ms,
DL speed drops to 0.10Mbps and upload speed drops to 0.02Mbps.

<span style="mso-spacerun:yes"> At these times the
Router Firewall Log reports 50 - 75 UDP floods, both inbound and outbound, and we
also see around 40 SYN Floods and TCP FIN Scans.

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I changed WiFi password and all the UDP floods have
stopped but we are still getting around 40 each of the SYN Floods and TCP FIN
Scans every day, all from WAN Outbound and all from the same IP addy which
happens to be the only desktop that has access to the Router.

<o:p> </o:p>

Now for my questions:

Any clues what I can do to stop all these SYN Floods and TCP
FIN Scans from happening?

Should I be concerned with either of these happening so
often?

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Sorry for the book here but I wanted to make sure I had
all the info anyone may need to possibly help me out!