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Re: NPF: newbie experiencing some strange behavior

On 6/17/14, 4:02 PM, g.lister wrote:
> The next rule there is
> +++
> pass out final all
> +++
> I think it should be evaluated as it is after the blocking of TCP
> transactions so UDP should be going out, but following your comment I
> played around with allowing everything and/or adding a rule for UDP
> and I could get some date from a look up only when I let everything
> in and out. I think I am forgetting something about DNS and how query
> responses are delivered...

Hi, George.

Is the "pass out final all" rule stateful by default?  If not, then your
UDP query may be going out, but NPF would be blocking the response since
I don't see a rule to pass it in.

A client DNS query usually uses a UDP connection to a DNS server on port
53, but it can sometimes use a TCP connection on port 53.  It will send
a query to the server and expect a response.  It looks like your NPF
rules might be blocking that response.

> Thanks Lewis for getting me going on that path.

Sure.  Hope you get it working!



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