I’ve been using Bind as a primary, slave or cache name server for all my IT life. But it seems Bind is being kicked out of OpenBSD. So far so good, I’m gonna use what’s provided by my favorite OS to do the job.
Here’s how to use nsd and unbound daemons to serve as an internal authoritative DNS nameserver and DNS resolver. Both will be running on the same machine.
Table of Contents
The server will be running OpenBSD 5.6 amd64. It ships with native nsd and unbound daemons. So since you install the OS, you get the toys.
# uname -a OpenBSD thundera.tumfatig.net 5.6 GENERIC.MP#333 amd64 # nsd -v NSD version 4.0.3 # unbound -dv  unbound[24599:0] notice: Start of unbound 1.4.22.
I’ll run both authoritative and resolver on the same host. I could either use different IP adresses and/or ports. Since I only have one authoritative nameserver, I don’t care using unusual ports. So I choose to use same IP and different ports. Only the resolver with query the authoritative nameserver.
Tell OpenBSD to start nsd on boot:
# vi /etc/rc.conf.local (...) nsd_flags="" (...)
Then edit the configuration file. The daemon will “bind” on port 8053 for all IPv4 adresses. I have 3 authoritative zones for which I want to use private name resolution.
# vi /var/nsd/etc/nsd.conf server: hide-version: yes ip-address: 0.0.0.0@8053 remote-control: control-enable: yes zone: name: "tumfatig.net" zonefile: "tumfatig.net" zone: name: "carnat.net" zonefile: "carnat.net" zone: name: "192.in-addr.arpa" zonefile: "192.in-addr.arpa"
The zone files are stored in
/var/nsd/zones/. Zones files are compatible with Bind format so you can simply scp them ; or use AXFR ; or write from scratch. The file name is the one referenced in the “zonefile” parameter.
That’s it. Just start the daemon and you’re done.
# /etc/rc.d/nsd start nsd(ok) # nsd-control status version: 4.0.3 verbosity: 0 ratelimit: 200 # nsd-control zonestatus tumfatig.net zone: tumfatig.net state: master # nsd-control zonestatus openbsd.org error zone openbsd.org not configured
The DNS resolver
The DNS resolver is the daemon that will query the DNS world on behalf of my LAN’s DNS clients. It’ll use Internet root DNS servers for general queries. For my “private” DNS zones, it will query the authoritative DNS nameserver previously created.
Tell the system that unbound will have to be launched at boot time:
# vi /etc/rc.conf.local (...) unbound_flags="" (...)
Then edit the configuration file. The daemon will listen on every IP adresses, usual port. It will be told to use the local nsd daemon for my private zones.
# vi /var/unbound/etc/unbound.conf server: interface: 0.0.0.0 interface: ::0 access-control: 192.168.0.0/24 allow access-control: 127.0.0.0/8 allow access-control: ::0/0 refuse access-control: ::1 allow hide-identity: yes hide-version: yes auto-trust-anchor-file: "/var/unbound/db/root.key" local-zone: "168.192.in-addr.arpa." nodefault remote-control: control-enable: yes control-interface: 127.0.0.1 control-interface: ::0 stub-zone: name: "tumfatig.net" stub-addr: 192.168.0.60@8053 stub-zone: name: "carnat.net" stub-addr: 192.168.0.60@8053 stub-zone: name: "0.168.192.in-addr.arpa." stub-addr: 192.168.0.60@8053
Control keys are to be created to enable remote management:
# unbound-control-setup setup in directory /var/unbound/etc generating unbound_server.key (...) generating unbound_control.key (...) create unbound_server.pem (self signed certificate) create unbound_control.pem (signed client certificate) (...) Setup success. Certificates created. Enable in unbound.conf file to use
By default, those keys are used if they exists. So there’s nothing more to do.
That’s all. Now start the daemon and enjoy:
# /etc/rc.d/unbound start unbound(ok) # unbound-control status version: 1.4.22 verbosity: 1 threads: 1 modules: 2 [ validator iterator ] uptime: 8 seconds unbound (pid 5712) is running... # unbound-control list_stubs . IN stub prime: M.ROOT-SERVERS.NET. L.ROOT-SERVERS.NET. K.ROOT-SERVERS.NET. J.ROOT-SERVERS.NET. I.ROOT-SERVERS.NET. H.ROOT-SERVERS.NET. G.ROOT-SERVERS.NET. F.ROOT-SERVERS.NET. E.ROOT-SERVERS.NET. D.ROOT-SERVERS.NET. C.ROOT-SERVERS.NET. B.ROOT-SERVERS.NET. A.ROOT-SERVERS.NET. 2001:dc3::35 2001:500:3::42 2001:7fd::1 2001:503:c27::2:30 2001:7fe::53 2001:500:1::803f:235 2001:500:2f::f 2001:500:2d::d 2001:503:ba3e::2:30 126.96.36.199 188.8.131.52 184.108.40.206 220.127.116.11 18.104.22.168 22.214.171.124 126.96.36.199 188.8.131.52 184.108.40.206 220.127.116.11 18.104.22.168 22.214.171.124 126.96.36.199 carnat.net. IN stub noprime: 192.168.0.60 tumfatig.net. IN stub noprime: 192.168.0.60 168.192.in-addr.arpa. IN stub noprime: 192.168.0.60
So far, it took only a few couple of minutes to set this up.
Later on, I’ll dig around statistics for those ; and how to draw pretty graphics out of them.