[Snort-users] icmp pass rules

Stephen Reese rsreese at ...11827...
Fri Oct 24 01:35:54 EDT 2008


I would like pass echo reply's on the internal network but not all
ICMP traffic. Currently my rule passes all of the internal ICMP
traffic, it there a way to be specific when creating a pass a rule
with ICMP?

var HOME_NET [172.31.1.0/24,172.31.2.0/24,172.31.3.0/24,172.31.4.0/24,172.31.5.0/24]

#Who cares if internal hosts are pinging each other
pass icmp $HOME_NET any -> $HOME_NET any (msg:"ICMP Echo Reply"; sid:1000002;)

Thanks

On Wed, Oct 22, 2008 at 2:02 PM, Stephen Reese <rsreese at ...11827...> wrote:
> On Wed, Oct 22, 2008 at 1:32 PM, Joel Esler <eslerj at ...11827...> wrote:
>> Your rules have no "sid" keyword in them. You must put an sid number in
>> there above 1 million.
>> J
>
> Thank you Joel, got it with the following:
>
> #Ignore redirects from the main router
> var 3825ROUTER [172.31.1.1/32]
> pass icmp $3825ROUTER any -> $HOME_NET any (msg:"ICMP Destination
> Unreachable Protocol Unreachable"; sid:1000000;)
>
> #Chatty Minolta copiers
> var DI200 [172.31.1.223/32,172.31.1.240/32]
> pass icmp $DI200 any -> $3825ROUTER any (msg:"ICMP redirect net"; sid:1000001;)
>




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