[Snort-users] icmp pass rules

Stephen Reese rsreese at ...11827...
Fri Oct 24 09:02:04 EDT 2008


I would assume there's a pretty large penalty for using suppression?

http://www.snort.org/docs/snort_htmanuals/htmanual_260/node24.html

On Fri, Oct 24, 2008 at 7:59 AM, Joel Esler <joel.esler at ...1935...> wrote:
> You should suppression.
>
> --
> Joel Esler
> Sent from my iPhone
>
> On Oct 24, 2008, at 1:35 AM, "Stephen Reese" <rsreese at ...11827...> wrote:
>
>> 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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