Re: W2K TCP/IP Filtering

From: Steven L Umbach (n9rou_at_n0-spam-for-me-comcast.net)
Date: 08/28/04 

Date: Sat, 28 Aug 2004 18:08:02 GMT

It should not interfere with internet users accessing your website but my guess is
that you are trying to access the internet from that computer. I bet it you leave
tcp/ip filtering enabled but select permit all for just UDP it will work. The reason
is that tcp/ip filtering is somewhat stateful for TCP but not UDP in that for TCP it
knows that a return response was initiated from your computer and allows it in while
not for UDP which blocks return UDP packets from the ISP dns server with the name
resolution request. --- Steve

"Steve" <anonymous@discussions.microsoft.com> wrote in message
news:1ea401c48d1f$a7ac5c50$a501280a@phx.gbl...
>I have a new w2k web server getting ready to go online,
> and I'm having some problems with the tcp/ip filtering.
> Following the guide at http://www.shebeen.com/w2k/ for
> basic hardening, I've enabled TCP/IP filtering. Problem
> is that it seems to break the connection to our DNS
> servers (internet DNS servers with IPs specified in the
> TCP/IP address properties). When I disable the TCP/IP
> filtering, everything works as it should.
>
> The settings are: TCP Permit only 22,80,443,3389
> UDP permit only: 161,162
> Protocols: 6,8
>
> I know if I was running DNS on this machine, I'd need 53
> open, but I'm not sure why the filtering is blocking name
> resolution when connecting to an outside dns server.

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