DNS Caching and Forwarding with Unbound

This howto shows the steps needed to configure unbound for DNS caching and forwarding from the 192.168.1.0/24 network. It assumes the server’s IP address is 192.168.1.22 and is running RHEL/CentOS 7.

Installation

[root@rhce-server ~]# yum install unbound

Configure Systemd

[root@rhce-server ~]# systemctl enable unbound
ln -s '/usr/lib/systemd/system/unbound.service' '/etc/systemd/system/multi-user.target.wants/unbound.service'
[root@rhce-server ~]# ^enable^start
systemctl start unbound

Configure the Firewall

[root@rhce-server ~]# firewall-cmd --add-service=dns
success
[root@rhce-server ~]# firewall-cmd --add-service=dns --permanent
success

Configure Unbound

Unbound’s configuration is stored in /etc/unbound/unbound.conf.
By default unbound only listens on the loopback interface. Specify which interface you would like to use.

interface: 192.168.1.22

Allow queries from 192.168.1.0/24.

access-control: 192.168.1.0/24 allow

Disable DNSSEC.

domain-insecure: *

Forward uncached requests to OpenDNS.

forward-zone:
    name: *
    forward-addr: 208.67.222.222
    forward-addr: 208.67.220.220

Check Your Configuration

[root@rhce-server ~]# unbound-checkconf 
unbound-checkconf: no errors in /etc/unbound/unbound.conf

Restart the Unbound Service

[root@rhce-server ~]# systemctl restart unbound

Verify it is Working

Test from a different system on the network.

mooose:~ jglemza$ dig fark.com A @192.168.1.22

; <<>> DiG 9.8.3-P1 <<>> fark.com A @192.168.1.22
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60299
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

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

;; ANSWER SECTION:
fark.com.       43200   IN  A   64.191.171.200

;; Query time: 234 msec
;; SERVER: 192.168.1.22#53(192.168.1.22)
;; WHEN: Sat Mar 21 13:16:54 2015
;; MSG SIZE  rcvd: 42

Verify the record is now in unbound’s cache.

[root@rhce-server ~]# unbound-control dump_cache|grep fark.com
ns2.fark.com.   43197   IN  A   23.253.56.58
fark.com.   43197   IN  A   64.191.171.200
ns1.fark.com.   43197   IN  A   64.191.171.194
fark.com.   43197   IN  NS  ns1.fark.com.
fark.com.   43197   IN  NS  ns2.fark.com.
...

Googlebot and FreeDNS from afraid.org

Back on January 8th I canceled my Dreamhost account and began hosting my site off of my cable modem. Only receiving ~15 hits a day I figured I might as well save myself $120 a year. So I chose freedns.afraid.org to host my DNS. They were free and had all the options that I wanted, including working with Tomato.

After the switch I noticed that my traffic had declined dramatically, down to ~1 hit per day. So I starting doing a bit of investigating and found that Google was no longer crawling my site and had deleted my previous results. Logging into the Google Webmaster Tools I found that Google was having DNS issues connecting to my site. Well, after pulling my hair out for an evening I found that FreeDNS was blocking the googlebot from crawling my site.

Solution: I have switched my DNS provider to ZoneEdit. ZoneEdit offers similar features to that of FreeDNS. Now Google can access my site again, but I'm no longer in the results for some searches. I guess it will take some time. Yahoo and Live search were totally unaffected by FreeDNS.

So this is a warning to all people using FreeDNS and want Google to crawl their site.