27Apr/170

New operating systems Ubuntu 17.04 and CentOS 6.9 available now!

As of today, you can order the new operating systems Ubuntu 17.04 (replaces Ubuntu 16.10) and CentOS 6.9 (replaces CentOS 6.8) from us. Existing customers can upgrade within their customer control panel as well!

Ubuntu 17.04 can be combined with Webmin, LAMP, Webmin+LAMP as well as the Software Raid 1.

Apart from Webmin, LAMP, Webmin+LAMP and Software Raid 1, you can also combine CentOS 6.9 with cPanel and Plesk.

In addition to Ubuntu and CentOS, we offer you a wide range of Linux distributions (as well as Windows Server 2012/2016). Just click on "Customize & Order" on our VPS and dedicated servers overview sites and opt for the operating system that fits your needs - further details can be found on our website!

Posted by: Markus | Tagged as: , , , , No Comments
30Jun/160

New Operating Systems available: Fedora 24 and CentOS 6.8

Recently, two operating systems received an upgrade: Fedora is now available in version 24, replacing version 23. Also, CentOS 6.6 upgraded to 6.8. The latest versions are available at Contabo now!

Fedora 24 can be combined with Software RAID 1 and Webmin, the installation via VNC is possible!

You may combine CentOS 6.8 optionally with Software RAID 1, Webmin, LAMP, Webmin+LAMP, Plesk or cPanel - an installation via VNC is possible as well!

fedora24The basic panel of Fedora 24

Apart from Fedora 24 and CentOS 6.8, we do offer you a wide range of Linux distributions (as well as Windows Server 2008/2012). Just click on "Customize & Order" on our VPS and dedicated servers overview sites and opt for the operating system that fits your needs!

Further information can be found on our website!

13Jul/151

Configuring additional IP addresses

Upon ordering a Dedicated Server or VPS you will receive one IPv4 address and one /64 IPv6 subnet. As an example, this could be the IPv4 address 192.51.100.10 and the IPv6 subnet 2001:0db8:2a02:c200::/64.

Your server comes pre-configured with this IPv4 (192.51.100.10) and one IPv6 address (2001:0db8:2a02:c200:0000:0000:0000:0001). Additional IPv4 addresses can be ordered by contacting us at support@contabo.com or through our homepage when placing an order for a new server. These additional IPv4 address will not be added to your system automatically but will have to be configured manually.

The following will give an overview on how to configure additional IP addresses on the most popular operating systems. The server used in these examples has the primary IPv4 address 192.51.100.10 and will receive the additional IPv4 addresses 192.51.100.42 and 192.0.2.23. As a general rule we recommend configuring these addresses with a netmask of 255.255.255.255 (/32) and /64 respectively and without adding a new gateway.

CentOS 6.x

CentOS has all its network interface configuration files stored in /etc/sysconfig/network-scripts/. In order to configure additional IPv4 addresses, one virtual interface per additional IPv4 address has to be created. If the main interface is e.g. eth0, the virtual interfaces would be named eth0:0, eth0:1, eth0:2 and so on. Their configurations reside in individual configuration files named ifcfg-eth0:0, ifcfg-eth0:1, ifcfg-eth0:2 receptively.

#/etc/sysconfig/network-scripts/ifcfg-eth0:0
DEVICE=eth0:0
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.51.100.42
NETMASK=255.255.255.255

#/etc/sysconfig/network-scripts/ifcfg-eth0:1
DEVICE=eth0:1
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.0.2.23
NETMASK=255.255.255.255

Additional IPv6 addresses can be specified using the variable IPV6ADDR_SECONDARIES in the interface's primary configuration file (/etc/sysconfig/network-scripts/ifcfg-eth0 in case of eth0). Multiple addresses are separated by a white space:

#/etc/sysconfig/network-scripts/ifcfg-eth0
...
IPV6ADDR_SECONDARIES=2001:0db8:2a02:c200:0000:0000:0000:0002/64 2001:0db8:2a02:c200:0000:0000:0000:0003/64
...

To apply the changes, restart the network service:

service network restart

CentOS 7.x / Fedora

The network interface configuration files of both CentOS 7.x and Fedora are stored under /etc/sysconfig/network-scripts/. Additional IPv4 addresses can be added to the respective interface's configuration file by using variables of the pattern IPADDR0, IPADDR1, IPADDR2 and PREFIX0, PREFIX1, PREFIX2 etc., in case of e.g. eth0 this would be /etc/sysconfig/network-scripts/ifcfg-eth0:

#/etc/sysconfig/network-scripts/ifcfg-eth0
...
IPADDR0=192.51.100.42
PREFIX0=32
IPADDR1=192.0.2.23
PREFIX1=32
...

The old method using virtual interfaces as employed in CentOS 6.x and described above will also still work.

Additional IPv6 addresses can be specified using the variable IPV6ADDR_SECONDARIES in the interface's primary configuration file (/etc/sysconfig/network-scripts/ifcfg-eth0 in case of eth0). Multiple addresses are separated by a white space:

#/etc/sysconfig/network-scripts/ifcfg-eth0
...
IPV6ADDR_SECONDARIES=2001:0db8:2a02:c200:0000:0000:0000:0002/64 2001:0db8:2a02:c200:0000:0000:0000:0003/64
...

To apply the changes, restart the network service:

service network restart

cPanel

With cPanel there is no need to deal with configuration files. Log in to WHM and navigate to "IP Functions" » "Add a New IP Address". Enter the IP address, select subnet mask 255.255.255.255 and click "Submit":

cpanel-ip

Debian / Ubuntu

Debian's and Ubuntu's network interface configuration is stored in /etc/network/interfaces. Additional IP addresses can be assigned by adding them in separate iface192.51.100.42 and 192.0.2.23 to eth0 whose primary address is 192.51.100.10:

#/etc/network/interfaces
auto eth0
allow-hotplug eth0
iface eth0 inet static
address 192.51.100.10
netmask 255.255.255.255
gateway 192.51.100.1

iface eth0 inet static
address 192.51.100.42
netmask 255.255.255.255

iface eth0 inet static
address 192.0.2.23
netmask 255.255.255.255
...

Additional IPv6 addresses are configured similarly:

#/etc/network/interfaces
...
iface eth0 inet6 static
address 2001:0db8:2a02:c200:0123:4567:89ab:0001
netmask 112
gateway fe80::1
accept_ra 0
autoconf 0
privext 0


iface eth0 inet6 static
address 2001:0db8:2a02:c200:0000:0000:0000:0002
netmask 64
...

To apply the changes, restart the networking service:

service networking restart

Or:

ifdown eth0; ifup eth0

openSUSE

openSUSE has its network interface configuration files stored under /etc/sysconfig/network/. All settings concerning e.g. eth0 are saved in ifcfg-eth0, additional IPv4 and IPv6 addresses can be added using the pattern IPADDR_1, IPADDR_2, IPADDR_3 etc:

#/etc/sysconfig/network/ifcfg-eth0
...
IPADDR_1='192.51.100.42/32'
IPADDR_2='192.0.2.23/32'
IPADDR_3='2001:0db8:2a02:c200:0000:0000:0000:0002/64'
IPADDR_4='2001:0db8:2a02:c200:0000:0000:0000:0003/64'
...

To apply the changes, restart the network service:

service network restart

Windows Server 2008, 2012 and 2016

Open the "Network and Sharing Center" and click on "Local Area Connection".

In Windows Server 2016:  Open the "Network and Sharing Center" and click on "Ethernet".

ws2008_01

In the newly opened windows, click on "Properties".

ws2008_02

If you want to add an additional IPv4 address, select "Internet Protocol Version 4 (TCP/IPv4)" and click on "Properties".

ws2008_03

In the newly created windows, click on "Advanced..." and in the following one on "Add..." under "IP addresses"

ws2008_05

Enter the new IP address and its netmask into the dialog and then click "Add".

ws2008_06

The new IP address is now active.

ws2008_07

IPv6 addresses can be added similarly by selecting "Internet Protocol Version 6 (TCP/IPv6)":

ws2008_08

ws2008_09

ws2008_12

ws2008_13

4Jul/150

Creating static routes

All traffic in our network has to pass through our core-routers, additionally switch ports are configured in such a way that they only accept ethernet frames with mac addresses originating from these routers. Consequently, no layer-2 traffic is forwarded between switch ports and direct communication between servers, even when on the same subnet, is not possible. If you have multiple servers with us which use IPv4 addresses from the same subnet (usually /24), and you want these servers to exchange traffic between each other, you will have to create static routes on these servers to each other.

The following examples assume that the server with the IPv4 address 192.51.100.10 and the server with the IPv4 address 192.51.100.42 want to communicate with each other.

CentOS

In CentOS, you can add static routes to the route-file of the respective interface. In case of eth0, the file is called route-eth0 and located under /etc/sysconfig/network-scripts/. The below entry on server 192.51.100.10 adds a static to server 192.51.100.42:

#/etc/sysconfig/network-scripts/route-eth0
...
192.51.100.42/32 via 192.51.100.1 dev eth0

Vice versa, the server 192.51.100.42 needs a corresponding route to server 192.51.100.10:

#/etc/sysconfig/network-scripts/route-eth0
...
192.51.100.10/32 via 192.51.100.1 dev eth0

Alternatively, both servers can have a single route added to the whole /24 subnet:

#/etc/sysconfig/network-scripts/route-eth0
...
192.51.100.0/24 via 192.51.100.1 dev eth0

Debian / Ubuntu

Static routes in Debian and Ubuntu are saved to /etc/network/interfaces. Entries are added to the end of the file or under the iface sections of the respective interface. Assuming the interface to be eth0, the entry on server 192.51.100.10 would look like this:

#/etc/network/interfaces
...
up ip route add 192.51.100.42/32 via 192.51.100.1 dev eth0
down ip route del 192.51.100.42/32 via 192.51.100.1 dev eth0

On server 192.51.100.42, this would be the static route to 192.51.100.10:

#/etc/network/interfaces
...
up ip route add 192.51.100.10/32 via 192.51.100.1 dev eth0
down ip route del 192.51.100.10/32 via 192.51.100.1 dev eth0

It is also possible to add a static route to the whole /24 on both servers instead:

#/etc/network/interfaces
...
up ip route add 192.51.100.0/24 via 192.51.100.1 dev eth0
down ip route del 192.51.100.0/24 via 192.51.100.1 dev eth0

openSUSE

Static routes in openSUSE can be set in /etc/sysconfig/network/routes. On server 192.51.100.10, the static route to 192.51.100.42 is as follows:

#/etc/sysconfig/network/routes
...
192.51.100.42/32 192.51.100.1 - eth0

Conversely, the static route on 192.51.100.42 to 192.51.100.10:

#/etc/sysconfig/network/routes
...
192.51.100.10/32 192.51.100.1 - eth0

As an alternative, both servers can have a static route to the whole /24 subnet:

#/etc/sysconfig/network/routes
...
192.51.100.0/24 192.51.100.1 - eth0

Windows Server

To create a static route under Windows Server 2008 or 2012, please open the "Command Prompt" with administrative privileges. On server 192.51.100.10 enter the following:

route -p add 192.51.100.42 mask 255.255.255.255 192.51.100.1

The corresponding entry on server 192.51.100.42 is:

route -p add 192.51.100.10 mask 255.255.255.255 192.51.100.1

Setting the -p option makes the route persistent across reboots. If the route is meant to be temporary, you may omit -p.

Posted by: Andreas | Tagged as: , , , , No Comments
11Jul/140

CentOS 7.0 now available at Contabo!

Source: http://de.wikipedia.org/wiki/CentOS

Shortly after the release of CentOS 7.0 we would like to offer you as well the brand new version of the Linux distribution CentOS. As of now, the new version can already be ordered on our website.

However, the previous version, CentOS 6.5, will remain available at Contabo.

The current version supports upgrades such as SW-RAID and Webmin. According to the manufacturer, configuration tools like Plesk, cPanel and LAMP should be available within the next few weeks.

The major changes and innovations of CentOS 7.0:

• Kernel updated to 3.10.0
• Support for Linux Containers
• OpenJDK-7 as default JDK
• LVM-snapshots with ext4 and XFS
• Switch to systemd, firewalld and GRUB2
• XFS as default file system