Linksys firewall setup - port blocking

I have the Linksys BEFSX41 router/firewall -
I have been setting up the filters to block various port probes,
but there are only 20 entries - and I'm running out

However, I was wondering why I can't just block all ports,
and then just allow the specific ports like DNS, HTTP, FTP, etc -

It seems I tried this - but since the router is using NAT,
the high numbered NAT ports also appear to be blocked ?
These are the same numbers that sometimes appear as port probes.

It's like the filters are applied AFTER the NAT translation,
vs BEFORE the NAT translation on the native incoming traffic -

I'll have to try this "block all" again -
but maybe it's done "after" the NAT translation
so as to gain access to the translated IP addresses -
Phil -

How can you tell if all ports are blocked?
Did you run a grc.com test?
Most ports if not all should be blocked in the first place, you have to
*open* them one by one for particular applications.

Ron


"Phil Schuman" <(E-Mail Removed)> a écrit dans le message
de news:AvMqb.13808$(E-Mail Removed) y.com...
> I have the Linksys BEFSX41 router/firewall -
> I have been setting up the filters to block various port probes,
> but there are only 20 entries - and I'm running out
>
> However, I was wondering why I can't just block all ports,
> and then just allow the specific ports like DNS, HTTP, FTP, etc -
>
> It seems I tried this - but since the router is using NAT,
> the high numbered NAT ports also appear to be blocked ?
> These are the same numbers that sometimes appear as port probes.
>
> It's like the filters are applied AFTER the NAT translation,
> vs BEFORE the NAT translation on the native incoming traffic -
>
> I'll have to try this "block all" again -
> but maybe it's done "after" the NAT translation
> so as to gain access to the translated IP addresses -
> Phil -
>
>
>
>

On Fri, 07 Nov 2003 12:47:28 GMT, Phil Schuman spoketh

>I have the Linksys BEFSX41 router/firewall -
>I have been setting up the filters to block various port probes,
>but there are only 20 entries - and I'm running out

Filters are for blocking outgoing packets, not incoming. All incoming
ports are blocked by default.


Lars M. Hansen
www.hansenonline.net