Maybe you want to create a local repository?
For that you should download all packages from the public repository and save them in our local Ubuntu server hard drive.
If so this is the procedure:
First install the main applications:
sudo su
apt-get update
apt-get install apt-mirror apache2
Now create a directory on your harddisk to save all packages:
sudo su
mkdir /localrepo
Now, open the file /etc/apt/mirror.list and make the changes as shown below:
sudo su
nano /etc/apt/mirror.list
############# config ##################
#
set base_path /localrepo
#
# set mirror_path $base_path/mirror
# set skel_path $base_path/skel
# set var_path $base_path/var
# set cleanscript $var_path/clean.sh
# set defaultarch <running host architecture>
# set postmirror_script $var_path/postmirror.sh
# set run_postmirror 0
set nthreads 20
set _tilde 0
#
############# end config ##############
deb http://archive.ubuntu.com/ubuntu trusty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu trusty-updates main restricted universe multiverse
#deb http://archive.ubuntu.com/ubuntu trusty-proposed main restricted universe multiverse
#deb http://archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty-updates main restricted universe multiverse
#deb-src http://archive.ubuntu.com/ubuntu trusty-proposed main restricted universe multiverse
#deb-src http://archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse
clean http://archive.ubuntu.com/ubuntu
Control + O, save file. Control + X, close nano
In the above configuration file, you can add the Ubuntu source lists depending upon the 32bit and 64bit architectures and distribution you use.
Once you saved the configuration file, populate your repository using the following command:
sudo su
apt-mirror
You need to run this command every week to get new softwares/updates.
To configure in client side. Just open your client systems file /etc/apt/sources.list and add your local repository path:
sudo su
nano /etc/apt/sources.list
##########################
deb http://10.120.1.2/ubuntu trusty universe
deb http://10.120.1.2/ubuntu trusty main restricted
deb http://10.120.1.2/ubuntu trusty-updates main restricted
##########################
Here 10.120.1.2 is your Ubuntu server IP address
Control + O, save file. Control + X, close nano
The clients need not to be connected to the Internet to download packages.
The clients will get all packages from your Ubuntu local repository.
Source: https://wiki.debian.org/HowToSetupADebianRepository