contrib/try-all-ns/dnsmasq-2.68-try-all-ns

From: Jesse Glick <jglick@cloudbees.com>
To: dnsmasq-discuss@lists.thekelleys.org.uk
Subject: Re: [Dnsmasq-discuss] Ability to delegate to one server but fall
 back to another after NXDOMAIN?


On Wed, Jan 15, 2014 at 12:30 PM, Simon Kelley <simon@thekelleys.org.uk> wrote:
> > There's a (very old) patch in contrib/try-all-ns that would make a starting point
This does not apply against trunk, so I tried to rework it. The
following appears to do what I expect:

diff --git a/src/forward.c b/src/forward.c
index 8167229..76070b5 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -610,7 +610,11 @@ void reply_query(int fd, int family, time_t now)

   if ((RCODE(header) == SERVFAIL || RCODE(header) == REFUSED) &&
       !option_bool(OPT_ORDER) &&
-      forward->forwardall == 0)
+      forward->forwardall == 0 ||
+      /* try each in turn */
+      RCODE(header) == NXDOMAIN &&
+      option_bool(OPT_ORDER) &&
+      server->next != NULL)
     /* for broken servers, attempt to send to another one. */
     {
       unsigned char *pheader;