On Tue, Jul 2, 2013 at 1:59 PM, Kurt Roeckx <k...@roeckx.be> wrote: > Do you know NXDOMAIN returns? I think it returns just the same? >
I don't immediately see how getaddrinfo() alone can be used to tell whether or not an actual NXDOMAIN was received. A test with a small C program reveals that retval -11 errno 2 is returned both in the NXDOMAIN case and in the case where no nameservers could be found. > > So ntpd should just keep trying to resolv invalid hostnames? > That may seem like a waste of resources, but * Computers are mobile these days and DNS also changes from the perspective of those computers. A laptop may connect sometimes to a LAN where the domain name ntp.somecorp.private resolves to the address of a time server. On other LANs this name does not exist. * If the retry period is on the order of seconds then the resources used aren't very significant. * If the name of the time server never resolves and this is a problem then it's the admin's fault for failing to configure ntpd properly. I suppose the question really is, when should the admin be notified that there is a problem? Good question. Is there something wrong with ntpd just logging resolution failures and leaving it at that? Anyway, you be the judge. Best wishes, -- Thomas
