ISP and DNS port scanning!

[Rthoreau <Rthoreau@iwon.com>]

Hello:  fellow Debian users

I was going over my router logs and noticed that I am getting port scanned 
from my ISP, this has been happening for a while but I haven't had the time 
to look into it untill now.  I did a basic whois on the IP address and they 
show that it is my ISP, the destination is a DNS server that belongs to my 
ISP.

I sent an E-mail to abuse to see what they are going to do about it, but I am 
in need of some knowledge?  Is this common? is the DNS server trying to 
collect or verify information on my system?  If so why?  

I did do a google search on DNS port scanning and denial of service, but did 
not turn up anything that would explain this.  That is why I am asking for 
your suggestions.  They seem to be sending it about every 30 seconds, so in 
effect they are using a denial of service against me.  Below is a few lines 
of my router log. 

In this format->  Time    Message         Source  Destination     Notes
 
11/18/2003 14:53:24     Firewall default policy: ICMP (W to W/ZW, type:8, 
code:0)         66.61.104.72    66.61.118.206   ACCESS BLOCK
14
        11/18/2003 14:53:20     Firewall default policy: ICMP (W to W/ZW, 
type:8, 
code:0)         66.61.30.31     66.61.118.206   ACCESS BLOCK
15
        11/18/2003 14:53:08     Firewall default policy: ICMP (W to W/ZW, 
type:8, 
code:0)         66.61.81.46     66.61.118.206   ACCESS BLOCK
16
        11/18/2003 14:52:45     Firewall default policy: ICMP (W to W/ZW, 
type:8, 
code:0)         66.61.123.234   66.61.118.206   ACCESS BLOCK
17

If this is common would someone please point me to a source to get more 
information.

Thanks;

Rthoreau at iwon dot com