Why is my DNS server not forwarding?

Question

I have setup bind like this:

//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//

options {
        listen-on port 53 { any; };
#       listen-on-v6 port 53 { ::1; };
        directory       "/var/named";
        forwarders      { 10.90.0.135; 10.90.0.174; };
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
        allow-query     { any; };
        recursion yes;

        dnssec-enable yes;
        dnssec-validation yes;
        dnssec-lookaside auto;

        /* Path to ISC DLV key */
        bindkeys-file "/etc/named.iscdlv.key";

        managed-keys-directory "/var/named/dynamic";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "." IN {
        type hint;
        file "named.ca";
};

include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";


zone "appletop.local" IN {
        type master;
        file "appletop.local";
        allow-update { none; };
};

But it doesn't forward?

If I just put the DNS server address into resolv.conf on another machine I get the correct lookups so the DNS server must be able to resolve for me but if I then point the other machine back at this one it cannot resolve the names.

What's wrong?

---

After changes suggested by MadHatter:

Now it starts but hangs on a dig +trace and doesn't forward - why do I not see the forwarders addresses below?

[root@ns1 ~]# ping www.yahoo.com
^C
[root@ns1 ~]# cd /etc/
[root@ns1 etc]# cp named.conf named.conf.last
[root@ns1 etc]# vi named.conf
[root@ns1 etc]# /etc/init.d/named reload
Reloading named-sdb:                                       [  OK  ]
[root@ns1 etc]# service named stop
Stopping named: .                                          [  OK  ]
[root@ns1 etc]# /etc/init.d/named start
Starting named:                                            [  OK  ]
[root@ns1 etc]# nslookup www.yahoo.com
;; connection timed out; trying next origin
Server:         10.138.10.30
Address:        10.138.10.30#53

** server can't find www.yahoo.com: NXDOMAIN

And a dig with +trace:

[root@ns1 etc]# dig +trace www.yahoo.com

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.0.2.el6_4.6 <<>> +trace www.yahoo.com
;; global options: +cmd
.                       518400  IN      NS      E.ROOT-SERVERS.NET.
.                       518400  IN      NS      M.ROOT-SERVERS.NET.
.                       518400  IN      NS      I.ROOT-SERVERS.NET.
.                       518400  IN      NS      F.ROOT-SERVERS.NET.
.                       518400  IN      NS      G.ROOT-SERVERS.NET.
.                       518400  IN      NS      K.ROOT-SERVERS.NET.
.                       518400  IN      NS      B.ROOT-SERVERS.NET.
.                       518400  IN      NS      A.ROOT-SERVERS.NET.
.                       518400  IN      NS      C.ROOT-SERVERS.NET.
.                       518400  IN      NS      L.ROOT-SERVERS.NET.
.                       518400  IN      NS      J.ROOT-SERVERS.NET.
.                       518400  IN      NS      H.ROOT-SERVERS.NET.
.                       518400  IN      NS      D.ROOT-SERVERS.NET.

My entire file looks like this now - whats wrong?

 options {
         listen-on port 53 { any; };
 #       listen-on-v6 port 53 { ::1; };
         directory       "/var/named";
         dump-file       "/var/named/data/cache_dump.db";
         statistics-file "/var/named/data/named_stats.txt";
         memstatistics-file "/var/named/data/named_mem_stats.txt";
         allow-query     { any; };
         recursion yes;

         dnssec-enable yes;
         dnssec-validation yes;
         dnssec-lookaside auto;

         /* Path to ISC DLV key */
         bindkeys-file "/etc/named.iscdlv.key";

         managed-keys-directory "/var/named/dynamic"; };

 logging {
         channel default_debug {
                 file "data/named.run";
                 severity dynamic;
         }; };

 zone "." IN {
         type forward;
         forward first;
         forwarders { 10.90.0.135;
                      10.90.0.174;
                    } ; };

 include "/etc/named.rfc1912.zones"; include "/etc/named.root.key";


 zone "appletop.local" IN {
         type master;
         file "appletop.local";
         allow-update { none; }; };

Answer 1

You've told it what forwarders to use, but not when to use them. If you want it to use them for everything, instead of

zone "." IN {
        type hint;
        file "named.ca";
};

try

zone "." {
        type forward;
        forward first;
        forwarders { 10.90.0.135;
                     10.90.0.174;
                   } ;
} ;

Edit: OK, try the above instead. I don't get what you mean by "try to resolve locally first", though; you said you wanted it to forward.

Answer 2

In my case the problem was solved by only changing dnssec-validation yes; to dnssec-validation no;

Answer 3

Just in case it wasn't clear by the OP's comment below MadHatter's respond, "problem was dnssec", I'm posting this answer explicitly since I too found it solved my problem.

I've setup a caching, forwarding-only BIND server and it wasn't forwarding. The queries were going to the root server with a several-second-delay. Disabling the dnssec options fix this, now it is working as expected.

dnssec-enable no;
dnssec-validation no;
dnssec-lookaside auto;