DNS wildcard and DHCP with BIND vs dnsmasq

set up DNS wildcard for blah.dev

BIND configuration

/etc/bind/named.conf.local 
zone "dev" {
   type master;
   file "/etc/bind/db.dev";
};

run"named-checkconf named.conf.local"

/etc/bind/db.dev:  use the loopback address so the IP address is not affected by DHCP.
dev. 86400 IN SOA dev. hostmaster.dev. (
               20111101; serial yyyy-mm-dd
               10800; refresh every 15 min
                3600; retry every hour
                 3600000; expire after 1 month +
                86400 ); min ttl of 1 day
  IN NS dev.
  IN MX 10 dev.
  IN A 127.0.0.1
*.dev. IN A 127.0.0.1

named-checkzone dev db.dev

DHCP client configuration

• uncomment the line in /etc/dhcp/dhclient.conf: prepend domain-name-servers 127.0.0.1;
• sudo dhclient
• sudo /etc/init.d/bind9 restart

Testing

ping blah.dev will return 127.0.0.1

Set up dnsmasq for local DNS cache and DHCP

disable dnsmasq from networkmanager

sudo vim /etc/NetworkManager.conf.  comment out dnsmasq

sudo service network-manager restart

Install and configure dnsmasq

• sudo apt-get install dnsmasq
• sudo vim /etc/dnsmasq.conf
•     listen-address=127.0.0.1
•     address=/dev/127.0.0.1
•     address=/prod/127.0.0.1
• sudo service dnsmasq restart

Set up Apache for vhost_alias
 

mod_vhost_alias

• sudo a2enmod vhost_alias (this will enable module vhost_alias for loading). 
• sudo vi /etc/apache2/mods-available/vhost_alias.conf    (create one if not existing)

<VirtualHost *:80>
# get the server name from the Host: header and put in %0

 # this is for dev
RewriteCond %{HTTP_HOST} ^mongo.dev$
RewriteRule (.*) http://localhost:28017/_replSet


RewriteCond %{HTTP_HOST} ^mongo.snap$
RewriteRule (.*) http://192.168.1.100:28000/_replSet



UseCanonicalName Off

# include the server name in the filenames used to satisfy requests
VirtualDocumentRoot /var/www/vhosts/%0

<Directory />
# Global settings
Options FollowSymLinks
AllowOverride All
</Directory>

</VirtualHost>

DNS query tracing

dig @dns.server target.dns +tracing

watch it under wireshark, It is very useful to understand how DNS query works especially for a non-cached look up.

• As a DNS client, dig will send a standard DNS query to the target DNS server via UDP port 53. 
• For a non-cached look up, dig will ask the answer from root server, TLD (Top Level Domain) server, specific domain server in that order.