I am using manual configuration to connect to my WLAN. In my wpa_supplicant.conf, I have something like this:

network={
    ssid="mywifi"
    key_management=WPA-EAP
    ...
}


and then, in my /etc/network/interfaces I have 

auto wlan0
    iface wlan0 inet dhcp


When I start my laptop, the connection to my WLAN is established automatically. The problem is, it takes sometimes 10 - 15 seconds until the connection is established and the whole boot process is blocked and waiting. 

I was wondering whether it is possible to configure, so that the connection is established in the background, so that the boot process can go on booting, without waiting for the WLAN to be ready.

I am using Debian Wheezy


Question: Is it necessary to run own DNS server?
Answer: Your domain name registrar should be hosting your DNS records. This is not something you have to do or worry too much about. In fact, you are far better off not running a DNS server because of the security implications. When you register your domain name many registrars will host your DNS records free of charge. Some do charge a small fee. If your registrar for some extremely odd reason cannot host your DNS records, there are DNS hosts. So there are plenty of options. I suggest making this a question you ask the registrar prior to registering your domain name.