Re: CAN-2004-1137

 From TCP/IP Illustrated, Volume I, pp. 79:

"Like ICMP, IGMP is considered part of the IP layer.  Also like ICMP, 
IGMP messages are transmitted in IP datagrams."

Basically, it is an IP datagram with a protocol # of 2.  The second 
32-bit chunk is the 32-bit group address, which is a Class D IP address: 
224.0.0.0/4.  Block that on INPUT using itpables and you should not see 
those packets again.

iptables -A INPUT -s 224.0.0.0/4 -j DROP 
iptables -A INPUT -d 224.0.0.0/4 -j DROP 


 Charles E. Hill

hilton de meillon wrote:

> I have been doing a bit of research - there are numerous instances of
>iptables scripts containing rules to block IGMP using iptables - am I
>correct in saying that IGMP is on the network layer IP protocol 2 hence all
>the iptables rulesets claiming to block igmp are misinformed ?.
>
>Is there a igmptables or any other way of selectively blocking IGMP using
>linux ?.
>
>Hilton.
>  
>