Re: [lwip-devel] Assertion fails in dns.c after PPP interface is down

[Sylvain Rochet]

Hello Jan,


On Mon, Jun 22, 2015 at 12:35:10PM +0200, Jan Breuer wrote:
> Hi Sylvain,
> your proposal is not a solution. Not for all cases.

Yes, I know ;-)


> I have discovered this behaviour also in common Ethernet network where the
> user can set all network parameters of the device including DNS. Setting
> DNS to 0.0.0.0 is still valid operation - disable DNS functionality at
> runtime - and all calls to dns_gethostbyname should return "not found". It
> don't mind, if we are in PPP, Ethernet with static address or we have
> address assigned by DHCP which does not tell us DNS server.

That's a very valuable input. I expected lwIP users (i.e. developers) to 
never switch back to ANY for all DNS servers and I actually considered 
what I did in PPP stack a mistake.

You are right, users of lwIP users (i.e. customers) might be able to set 
up DNS server to NULL in order to configure their device to -never- try 
name resolution, for example in a closed network without DNS support.

It pushes forward into applying Michael patch which consider all cases 
instead of applying my patch to "fix" the PPP stack.


Sylvain

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