> Can you pass a nameserver to use to resolving functions normally? No. As you suspect the name server is never passed to these functions. The reason for that is that in context of a DNS query the name server address is static, independent of the query. Of course for debugging purposes, when something does not work and I need to simulate the resolver work (by querying by hand from a command line), I make sure to specify the name server address. Note that the name server address is the first argument to "dig". But this is needed only because something does not work correctly.
> At least I have never used such functions but always relied on the OS to > select the correct namesever. Well, technically the OS does not select the server, nor does it select the "correct" server. You, your admin, or the DHCP server configured by you, or by your admin, configure the DNS resolver giving it the addresses of one or more name servers you want to be used later when you run your DNS query. The resolver then iterates over the name servers which themselves may recurse on the query (contact another name server) until the name is translated or until there is no more name server to try. So there actually isn't a "correct" server, all you can say is the order in which the servers will be contacted. Cheers, -Z ________________________________________ From: [email protected] [[email protected]] on behalf of Simon Goldschmidt [[email protected]] Sent: Saturday, August 16, 2014 1:55 PM To: Mailing list for lwIP users Subject: Re: [lwip-users] Split DNS for multihomed setup Sergio R. Caprile wrote: > This to me is the same source routing issue and you will > face it for every application in which you need some specific > destination associated to a specific source address/interface. It is, but this one is an additional problem to make one application use the source based routing. And DNS is one of the few application level protocols that are shipped with core lwIP. And no, I don't have a better idea than the suggested changes you made to dns.c. But is this anything like standard dns? Can you pass a nameserver to use to resolving functions normally? At least I have never used such functions but always relied on the OS to select the correct namesever. Simon _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users
