====== Network ======

===== Ports =====

^Port^Protocol^
|  20 + 21  |  FTP  |
|  22  |  SSH  |  
|  25  |  SMTP  | 
|  80  |  HTTP  |
|  111 + 2049  |  TCP/UDP - NFS  |
|  123  |  UDP - NTP  |
|  137 + 139 + 445  |  TCP/UDP - SMB/Samba  |
|  443  |  HTTPS  |
|  8080  |  Proxy  |
|  3389  |  RDP  |
|  3306  |  MySQL  | 

===== Configuration =====


==== Proxy ====

For your account only edit:
<code>
sudo vi /home/<username>/.bashrc
</code>
\\
For global proxy edit:
<code>
sudo vi /etc/profile
</code>
add
<code>
export http_proxy=http://10.0.0.1:8080
export https_proxy=https://10.0.0.1:8080
</code>
\\
Reload your configuration
<code>
source /home/<username>/.bashrc

or

source /etc/profile
</code>

=== Set proxy for apt ===

Open apt.conf
<code>
vi /etc/apt/apt.conf
</code>

Set proxy
<code>
Acquire::http::Proxy "http://127.0.0.1:8080";
Acquire::https::Proxy "https://127.0.0.1:8080";
</code>

=== Set proxy for wget ===

Open wgetrc
<code>
vi ~/.wgetrc
</code>

Set proxy
<code>
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
</code>

OR

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

==== Change your IP (Ubuntu < 16) ====

Edit /etc/network/interfaces:
<code>
sudo vi /etc/network/interfaces
</code>
and add
<code>
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
</code>
Restart your networkinterface
<code>
/etc/init.d/networking restart
</code>
<code>
ifdown eth0 && ifup eth0
</code>

==== Change your IP (Ubuntu > 16) ====

Edit /etc/netplan/01-netcfg.yaml:
<code>
sudo vi /etc/netplan/01-netcfg.yaml
</code>
and add
<code>
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]
</code>
Apply the new IP config
<code>
sudo netplan apply
</code>

==== Change your IP (SLES11/12) ====

Edit /etc/sysconfig/network/ifcfg-eth0:
<code>
sudo vi /etc/sysconfig/network/ifcfg-eth0
</code>
and add
<code>
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=''
</code>

Edit gateway /etc/sysconfig/network/routes:
<code>
sudo vi /etc/sysconfig/network/routes
</code>
and add
<code>
default 10.0.0.1 - eth0
#default 10.0.0.1 - -
</code>

Restart your networkinterface

SLES11
<code>
/etc/init.d/networking restart
</code>

SLES12
<code>
ifdown eth0 && ifup eth0
</code>

==== Join a domain and change hostname ====

Edit /etc/hosts
<code>
sudo vi /etc/hosts
</code>
and add
<code>
127.0.0.1       localhost.localdomain localhost
127.0.1.1       ubuntu.lunetikk.de ubuntu
10.0.0.2        ubuntu.lunetikk.de ubuntu
</code>
\\
\\
Open /etc/hostname and change the entry to your new hostname (for example: ubuntu)
<code>
sudo vi /etc/hostname
</code>
Set your hostname
<code>
hostname –F /etc/hostname
</code>

New syntax to set a hostname
<code>
hostnamectl set-hostname "YOURHOSTNAME"
</code>
Show hostname
<code>
hostnamectl
</code>

==== Tools to monitor traffic ====

[[https://askubuntu.com/questions/257263/how-to-display-network-traffic-in-the-terminal|Askubuntu - Tools to display traffic]]

<code>

#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

</code>
bmon: {{:linux:general:pasted:20190416-135948.png?400}}

tcptrack: {{:linux:general:pasted:20190416-141118.png?400}}

nload: {{:linux:general:pasted:20190416-141355.png?400}}

iftop: {{:linux:general:pasted:20190416-141728.png?400}}

ethstatus: {{:linux:general:pasted:20190416-141835.png?400}}
==== Troubleshooting ====

=== resolv.conf is empty ===

<code> dpkg-reconfigure resolvconf </code>

=== Cant do ifdown/ifup ===

<code>
# 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
</code>

This should fix it:
<code> apt-get --purge remove sendmail sendmail-base sendmail-bin </code>

\\
\\
~~DISCUSSION:closed~~