Re: ICMP filter

Dan Struthers (dstruth@bserv.com)
Sat, 5 Apr 1997 11:11:15 -0500

When you specify the name of the filter, leave off the extension. The PM
assumes the ext of .in so now it is looking for icmp.in.in which it won't find.

>I'm having trouble with flitering ICMP ECHO packets from the modems. I
>set the filter and it seems that the input filter isn't even there. I
>ptrace the filter though and it gives me the desired packet tracing
>effect. Perhaps someone can tell me the error in my reasoning.
>first, I add filter icmp.in
>Then I set the filter with these params
> 1 permit 208.9.136.0/24 0.0.0.0/0 icmp
> 2 permit 208.9.209.0/24 0.0.0.0/0 icmp
> 3 permit 0.0.0.0/0 208.9.136.82/32 icmp
> 4 deny 0.0.0.0/0 208.9.136.0/24 icmp type 8
> 5 deny 0.0.0.0/0 208.9.209.0/24 icmp type 8
> 6 permit 0.0.0.0/0 0.0.0.0/0 icmp
> 7 permit 0.0.0.0/0 0.0.0.0/0 tcp
> 8 permit 0.0.0.0/0 0.0.0.0/0 udp
>Being that 208.9.136.0/24 and 208.9.209.0/24 are domains, and
>208.9.136.82 is the main machine. The object is to filter out all ICMP
>ECHO to the modems except from the two domains.
>I then set S43 if icmp.in (my current port S43)
>And finally save all.
>But again, it just seems that the filter is not in place.
>Thanks for any help, I need it :)
>
>******************************************
> Eric Mellon
> UNIX Systems Administrator
> Delanet Inc. http://www.delanet.com
>"God will save my soul, if I have a soul."
>******************************************
>
>
>
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Dan Struthers

The solution to any problem lies in its proper definition.
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