locked out of postfix install

[Aaron Gray <aaronngray.lists@gmail.com>]

Hi,

I have a relatively fresh install of Debian 8

I did a

sudo apt-get install postfix

The treminal then came up with a page with instructions and an <OK>
button, I then left this while I was waiting for my DNS change to
resolve which took several hours. When I went back to the terminal it
was frozen. I tried ctrl-D,C, and Z. I then had to kill the terminal
with the close button.

Then I found dpkg still running and had to kill that as apt-get would
no longer run.

Hears my sources.list file, not sure thats relevant or will help ?

~~~ /etc/apt/sources.list ~~~
# deb cdrom:[Debian GNU/Linux 8.3.0 _Jessie_ - Official amd64 DVD
Binary-1 20160123-19:03]/ jessie contrib main

#deb cdrom:[Debian GNU/Linux 8.3.0 _Jessie_ - Official amd64 DVD
Binary-1 20160123-19:03]/ jessie contrib main

deb http://ftp.uk.debian.org/debian/ jessie main
deb-src http://ftp.uk.debian.org/debian/ jessie main

deb http://security.debian.org/ jessie/updates main contrib
deb-src http://security.debian.org/ jessie/updates main contrib

# jessie-updates, previously known as 'volatile'
deb http://ftp.uk.debian.org/debian/ jessie-updates main contrib
deb-src http://ftp.uk.debian.org/debian/ jessie-updates main contrib
~~~

Hope you can help ! I would rather not do a fresh install if it can be avoided.

Many thanks in advance,

Aaron