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:

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:

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:

netplan try

Apply the changes:

netplan apply

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

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:

/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:

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:

systemctl restart network

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

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