For your account only edit:

sudo vi /home/<username>/.bashrc

sudo vi /etc/profile

export http_proxy=http://10.0.0.1:8080
export https_proxy=https://10.0.0.1:8080

source /home/<username>/.bashrc

or

source /etc/profile

Open apt.conf

vi /etc/apt/apt.conf

Set proxy

Acquire::http::Proxy "http://127.0.0.1:8080";
Acquire::https::Proxy "https://127.0.0.1:8080";

Open wgetrc

vi ~/.wgetrc

Set proxy

use_proxy=on
http_proxy=127.0.0.1:8080
https_proxy=127.0.0.1:8080
http_proxy=http://username:password@proxy_host:proxy_port
https_proxy=https://username:password@proxy_host:proxy_port

OR

wget <URL> -e use_proxy=on -e http_proxy=127.0.0.1:8080

Edit /etc/network/interfaces:

sudo vi /etc/network/interfaces

auto eth0
iface eth0 inet static
        address 10.0.0.2
        netmask 255.0.0.0
        network 10.0.0.0
        broadcast 10.0.0.255
        gateway 10.0.0.1
        dns-nameservers 10.0.0.1

/etc/init.d/networking restart

ifdown eth0 && ifup eth0

Edit /etc/netplan/01-netcfg.yaml:

sudo vi /etc/netplan/01-netcfg.yaml

network:
  version: 2
  renderer: networkd
  ethernets:
    ens3:
      dhcp4: no
      addresses:
        - 10.0.0.2/8
      gateway4: 10.0.0.1
      nameservers:
          addresses: [8.8.8.8, 8.8.4.4]

sudo netplan apply

Edit /etc/sysconfig/network/ifcfg-eth0:

sudo vi /etc/sysconfig/network/ifcfg-eth0

DEVICE='eth0'
BOOTPROTO='static'
STARTMODE='auto'
USERCONTROL='no'
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR='10.0.0.2'
MTU=''
NAME=''
NETMASK='255.255.255.0'
NETWORK=''
REMOTE_IPADDR=''

Edit gateway /etc/sysconfig/network/routes:

sudo vi /etc/sysconfig/network/routes

default 10.0.0.1 - eth0
#default 10.0.0.1 - -

Restart your networkinterface

SLES11

/etc/init.d/networking restart

SLES12

ifdown eth0 && ifup eth0

Edit /etc/hosts

sudo vi /etc/hosts

127.0.0.1       localhost.localdomain localhost
127.0.1.1       ubuntu.lunetikk.de ubuntu
10.0.0.2        ubuntu.lunetikk.de ubuntu

sudo vi /etc/hostname

hostname –F /etc/hostname

New syntax to set a hostname

hostnamectl set-hostname "YOURHOSTNAME"

hostnamectl

Askubuntu - Tools to display traffic

#bmon - shows multiple interfaces at once
apt-get install bmon

#tcptrack - Tells how much bandwidth is being used and also what protocol (service/port) and destination the transmission is taking place to. Very helpful when you want to know exactly what is using up your bandwidth
apt-get install tcptrack

#nload - Separated view for down and upload
apt-get install nload

#iftop
apt-get install iftop

#ethstatus
apt-get install ethstatus

tcptrack:

nload:

iftop:

ethstatus:

 dpkg-reconfigure resolvconf 

# ifdown eth0 && ifup eth0
/etc/resolvconf/update-libc.d/sendmail: 7: .: Can't open /usr/share/sendmail/dynamic
run-parts: /etc/resolvconf/update-libc.d/sendmail exited with return code 2
run-parts: /etc/resolvconf/update.d/libc exited with return code 1
/etc/resolvconf/update-libc.d/sendmail: 7: .: Can't open /usr/share/sendmail/dynamic
run-parts: /etc/resolvconf/update-libc.d/sendmail exited with return code 2
run-parts: /etc/resolvconf/update.d/libc exited with return code 1
/etc/network/if-up.d/sendmail: 44: .: Can't open /usr/share/sendmail/dynamic
run-parts: /etc/network/if-up.d/sendmail exited with return code 2

This should fix it:

 apt-get --purge remove sendmail sendmail-base sendmail-bin