Hostname is more of a UNIX thing than a Mac thing ;-) It can be changed in the Sharing section of System Preferences where it is known as Computer Name.
ping hostname or nslookup hostname For more details: http://www.zilckh.com/how-to-find-ip-address-from-hostname-in-a-windows-system-using-command-line/
no hostname
Type hostname mand enter
hostname.
With the following command: No hostname
The hostname (the name of the computer) can be found in most Linux distributions by issuing the hostname command without arguments. Alternatively, you can view the contents of /etc/hosts. The hostname will be listed next to the IP address 127.0.1.1.
A hostname is the name a computer uses to identify itself to other computers on a network.
A hostname in an email address appears after the @ symbol, like user@hostname.com. The hostname is always the company or group that handles that email address.
on the very right hand side of your hotmail account you will see a button "options" this will give you a menu, at the bottom of this menu there is an option " more options" This will lead you to a page an there you will find a section called "Junk Email" in this section there is a subsection called "safe and blocked Senders" if you go into this section you will see a small section called "blocked Senders" in here you can add the address of anyone you want to block
DNS issue
The MAC store or on their website.
You cant sry its not on mac