newbie: question about forwarders

KSP ksp at att.com
Wed Aug 25 19:22:33 UTC 2004


Mike,

The error message pretty much says it all.  You are forwarding to servers
that are not recursive -- these are probably your ISP's authoritative name
servers.

> 1) am I wrong in my thinking the nameservers of my isp would make great
> forwarders?. I think they could answer a lot of my queries from cache?

You can recurse yourself or forward to your ISP's recursers.  I don't know
of any standard or recommendation either way.  But you have to make sure
you are forwarding to the correct servers.

> 2) Why on earth would my isp make the nameservers non-recursive? What's
> the point, whats in it for them?

Because it's best current practice to have your authoritative and
recursive servers be separate entities.  You just happen to be pointing at
the wrong set of servers.  Call your ISP and ask them what their recursive
DNS servers are.

An easy way to tell if a server is not recursive is to query it for a
resource record you are mostly certain it *isn't* authoritative for.  If
you get the root servers back as your result, its safe to assume it is not
configured to recurse:

-----snip-----
[me at host] dig @194.109.9.100 yahoo.com

; <<>> DiG 9.2.1 <<>> @194.109.9.100 yahoo.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51940
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 13, ADDITIONAL: 13

;; QUESTION SECTION:
;yahoo.com.                     IN      A

;; AUTHORITY SECTION:
.                       394993  IN      NS      I.ROOT-SERVERS.NET.
.                       394993  IN      NS      E.ROOT-SERVERS.NET.
.                       394993  IN      NS      D.ROOT-SERVERS.NET.
.                       394993  IN      NS      A.ROOT-SERVERS.NET.
.                       394993  IN      NS      H.ROOT-SERVERS.NET.
.                       394993  IN      NS      C.ROOT-SERVERS.NET.
.                       394993  IN      NS      G.ROOT-SERVERS.NET.
.                       394993  IN      NS      F.ROOT-SERVERS.NET.
.                       394993  IN      NS      B.ROOT-SERVERS.NET.
.                       394993  IN      NS      J.ROOT-SERVERS.NET.
.                       394993  IN      NS      K.ROOT-SERVERS.NET.
.                       394993  IN      NS      L.ROOT-SERVERS.NET.
.                       394993  IN      NS      M.ROOT-SERVERS.NET.

;; ADDITIONAL SECTION:
I.ROOT-SERVERS.NET.     481393  IN      A       192.36.148.17
E.ROOT-SERVERS.NET.     481393  IN      A       192.203.230.10
D.ROOT-SERVERS.NET.     481393  IN      A       128.8.10.90
A.ROOT-SERVERS.NET.     481393  IN      A       198.41.0.4
H.ROOT-SERVERS.NET.     481393  IN      A       128.63.2.53
C.ROOT-SERVERS.NET.     481393  IN      A       192.33.4.12
G.ROOT-SERVERS.NET.     481393  IN      A       192.112.36.4
F.ROOT-SERVERS.NET.     481393  IN      A       192.5.5.241
B.ROOT-SERVERS.NET.     481393  IN      A       192.228.79.201
J.ROOT-SERVERS.NET.     481393  IN      A       192.58.128.30
K.ROOT-SERVERS.NET.     481393  IN      A       193.0.14.129
L.ROOT-SERVERS.NET.     481393  IN      A       198.32.64.12
M.ROOT-SERVERS.NET.     481393  IN      A       202.12.27.33

;; Query time: 166 msec
;; SERVER: 194.109.9.100#53(194.109.9.100)
;; WHEN: Wed Aug 25 19:21:25 2004
;; MSG SIZE  rcvd: 446
-----snip-----

Good luck,

ksp

On Wed, 25 Aug 2004, Mike wrote:

> /me bows before all bind guru's.
>
> I have just started to explore bind and set up a local nameserver following
> the directions in the book DNS and BIND, 4th Edition. By Paul Albitz,
> Cricket Liu . It works.and I am about to explore further. but still I've
> got this question about forwarders.
>
> I put the ip adresses of the 2 nameservers of my isp as forwarders in
> named.conf but in /var/log/messages I now get the message:
>
>
> Aug 25 18:48:53 ns named[73]: Ready to answer queries.
> Aug 25 18:48:53 ns named[73]: non-recursive forwarder: [194.109.9.100].53
> Aug 25 18:48:53 ns named[73]: non-recursive forwarder: [194.109.6.67].53
>
> I googled this quite a bit but I cant find answers to the following
> questions:
>
> 1) am I wrong in my thinking the nameservers of my isp would make great
> forwarders?. I think they could answer a lot of my queries from cache?
>
> 2) Why on earth would my isp make the nameservers non-recursive? What's the
> point, whats in it for them?
>
> Thanx for helping a newbie.. for config files see below
>
>
> >------------------------------------------------------------------<
>
>
> $ cat named.conf ddesk.nl.db db.192.168.1 db.127.0.0
>
> -> named.conf <-
>
> // $FreeBSD: src/etc/namedb/named.conf,v 1.6.2.7 2003/02/13 13:16:51
> keramida Exp $
> //
>
> options {
>          directory "/etc/namedb";
>          forwarders { 194.109.6.67; 194.109.9.100; };
>         };
> /* logging  {
>  channel my_syslog {
>    syslog daemon;
>    severity dynamic;
>    print-category yes;
>    print-severity yes;
>   };
>  channel my_file {
>    file "log.msgs";
>    severity dynamic;
>    print-category yes;
>    print-severity yes;
>  };
>  category default {my_syslog;my_file;};
>  category statistics {my_syslog;my_file;};
>  category queries {my_syslog;my_file;};
> };
> */
> zone "ddesk.nl" in
> {
>         type master;
>         file "ddesk.nl.db";
> };
>
> zone "1.168.192.in-addr.arpa"
> {
>         type master;
>         file "db.192.168.1";
> };
>
> zone "0.0.127.in-addr.arpa" in
> {
>         type master;
>         file "db.127.0.0";
> };
>
> zone "."
> {
>         type hint;
>         file "db.cache";
> };
>
> -> ddesk.nl.db <-
>
> $TTL 3h
> ddesk.nl.       IN      SOA ns.ddesk.nl. hostmaster.domain.com. (
>         2004081712      ;serial number
>         3h              ;refresh after 3 hours
>         1h              ;retry after 1 hour
>         1w              ;expire  after 1 week
>         1h      )       ;negative caching TTL of 1hour
> ;
> ;Nameserver
> ddesk.nl.               IN      NS      ns.ddesk.nl.
> ;
> ;Addresses
> ns      IN      A       192.168.1.101
> laptop  IN      A       192.168.1.201
> wp2     IN      A       192.168.1.202
> wp3     IN      A       192.168.1.203
>
> -> db.192.168.1 <-
>
> $TTL 3h
> 1.168.192.in-addr.arpa. IN SOA ns.ddesk.nl. hostmaster.ddesk.nl. (
>                 2004081712      ;serial
>                 3h              ;refresh rate (3 hours)
>                 1h              ;retry (1 hour)
>                 1w              ;expire (1 week)
>                 1h )            ;negative caching TTL (1 hour)
> ;
> ; Name server
> 1.168.192.in-addr.arpa. IN      NS      ns.ddesk.nl.
> ;
> ;Adresses
> 101     IN      PTR     ns.ddesk.nl.
> 201     IN      PTR     laptop.ddesk.nl.
> 202     IN      PTR     wp2.ddesk.nl.
> 203     IN      PTR     wp3.ddesk.nl.
>
> -> db.127.0.0 <-
>
> $TTL 3h
> 0.0.127.in-addr.arpa. IN SOA ns.ddesk.nl. hostmaster.ddesk.nl. (
>                 2004081001      ; serial
>                 3h              ; refresh after 3 hours
>                 1h              ; retry after 1 hour
>                 1w              ; expire after 1 week
>                 1h )            ; negative caching TTL of 1 hour
>
> 0.0.127.in-addr.arpa.   IN NS ns.ddesk.nl.
>
> 1.0.0.127.in-addr.arpa. IN PTR localhost.
>
> EOF
>
>


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