Networking
**********

How to find the Default Gateway IP Address?
===========================================

If your VPS is not reachable, please check your local network configuration settings. In most cases the default gateway address 
is missing in the configuration file on Debian-based distributions.

The usable IP addresses and necessary information about the network
configuration (such as IP addresses or gateway address) can be found in our
customer portal:

https://my.virtualhosts.de/cloud/ => Control => Server Information => IPv4/IPv6 Settings

To change the network configuration, please edit the file /etc/network/interfaces as in the example below:

.. code-block:: console

   auto lo
     iface lo inet loopback
   auto eth0
     iface eth0 inet dhcp
     pre-up echo 0 > /proc/sys/net/ipv6/conf/eth0/accept_dad
    iface eth0 inet6 static
    address 2a02:e00:fffx:13e::1/64
    iface eth0 inet6 static
    address 2a02:e00:fffx:13e::2/64
    ...
    iface eth0 inet6 static
    address 2a02:e00:fffx:13e::a/64
       up ip -6 route add 2a02:e00:fff0::1 dev eth0
       up ip -6 route add default via 2a02:e00:fff0::1


Ubuntu 18 IPv6 configuration
============================

To change the network configuration, please edit the file /etc/netplan/50-cloud-init.yaml as in the example below:

.. code-block:: console
   
   network:
    version: 2
    ethernets:
        net0:
            accept-ra: no
            addresses:
            - 130.xxx.xxx.xx/24
            - "2a02:e00:xxxx:xx::x/64"
            - "2a02:e00:xxxx:xx::x/64"
            [...]
            gateway4: 130.xxx.xx.x
            gateway6: "2a02:e00:xxxx::x"
            match:
                macaddress: xx:xx:xx:xx:xx:xx
            nameservers:
                addresses:
                - 8.8.8.8
                - 8.8.4.4
                search: []
            routes:
            - to: "2a02:e00:xxxx::/64"
              via: "::"
              on-link: true              
            - to: "::/0"
              via: "2a02:e00:xxxx::"
              on-link: true
            set-name: net0

Check for syntax errors:

.. code-block:: console
   
    netplan try

Apply the changes:

.. code-block:: console
   
    netplan apply


To prevent cloud-init to configure your network after rebooting you need to disable it. Just set

.. code-block:: bash

    echo "network: {config: disabled}" > /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg


CentOS 8 IPv6 Network Configuration
===================================

CentOS 8 network configuration ist done via cloud-init. Due to a bug the IPv6 configuration isn't set properly. There are two configuration files created:

.. code-block:: bash

    /etc/sysconfig/network-scripts/ifcfg-net0
    /etc/sysconfig/network-scripts/ifcfg-net0:1

Unfortunately ifcfg-net0:1 will not be used. As a workaround you have to copy the configuration starting from **IPV6INIT** into your ifcfg-net0. This should look like this:

.. code-block:: bash

    BOOTPROTO=none
    DEFROUTE=yes
    DEVICE=net0
    GATEWAY=xxx.xxx.xxx.xxx
    HWADDR=32:c1:5d:46:29:42
    IPADDR=xxx.xxx.xxx.xxx
    NETMASK=255.255.255.0
    ONBOOT=yes
    STARTMODE=auto
    TYPE=Ethernet
    USERCTL=no
    IPV6INIT=yes
    NM_CONTROLLED="no"
    IPV6_DEFAULTGW=2a02:e00:ffec::1
    IPV6ADDR_SECONDARIES= "[...]"
    ip -6 route add 2a02:e00:ffec::1 dev net0
    ip -6 route add ::/0 via 2a02:e00:ffec::1 dev net0

After that you need to restart your network:

.. code-block:: bash

    systemctl restart network

To prevent cloud-init to configure your network after rebooting you need to disable it. Just set

.. code-block:: bash

    echo "network: {config: disabled}" > /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg