IPv6 configuration of network interfaces and domain name resolution under RedHat Linux

Introdution

IPv6 configuration of network interfaces under Suse Linux

IPv6 configuration of domain name resolution (DNS) under Suse Linux

Introdution

Besides of enabled IPv6 support, operating system needs a proper IPv6 configuration of network interfaces and domain name resolution (using DNS). Bellow the relevant sections are describing how to configure these elements in Suse Linux.

IPv6 configuration of network interfaces under Suse Linux

Here is a list of steps that must be performed to configure network interfaces to operate in an IPv6 network.

1. There are particular configuration files in /etc/sysconfig/network-scripts e.g. ifcfg-eth0 file for a network interface named eth0. There is no need of any additional entries besides those entries that already are in default configuration in case of the dynamic configuration (DHCP). In case of static configuration, specific addresses entries need to be inserted in particular network interface configuration file

1. The dynamic configuration (DHCPv6):

There should be following entry in /etc/sysconfig/network/ifcfg-interface_name:

• BOOTPROTO='dhcp'

For example: in case of eth0 the /etc/sysconfig/network/ifcfg-eth0 file should look like this:

BOOTPROTO='dhcp'
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR=''
MTU=''
NETMASK=''
NETWORK=''
REMOTE_IPADDR=''
STARTMODE='auto'
USERCONTROL='no' 

Attention! In Dual Stack mode (simultaneous support for IPv4 and IPv6) with the dynamic configuration there is a need of having two kind of DHCP servers working in the network: DHCPv4 and DHCPv6.

2. The static configuration:

There is IPADDR definition for defining static addresses. This definition is regardless of defining IPv4 or IPv6 adresses. Furthermore in case of multiple IP addresses for one interface, the configuration allows adding more characters to string IPADDR depending on their own concept such as:

• IPADDR1, IPADDR2, IPADDR3
• IPADDR_v4_1, IPADDR_v4_2, IPADDR_v6_1, IPADDR_v6_2

There should be following entry in /etc/sysconfig/network/ifcfg-interface_name:

• BOOTPROTO='static'

Therefore for example: in case of eth0 the /etc/sysconfig/network/ifcfg-eth0 file should look like this:

BOOTPROTO='static'
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR='31de::a00:2ff:fe5e:5e5a/96'
MTU=''
NETWORK=''
REMOTE_IPADDR=''
STARTMODE='auto'
USERCONTROL='no 

Attention! In Dual Stack mode with the static configuration there is a need of having IPv4 definition also (IPADDR). In that case a sample definitions for eth0 interface should be as follows:

BOOTPROTO='static'
BROADCAST=''
ETHTOOL_OPTIONS=''
IPADDR_v4='20.0.2.17/24'
IPADDR_v6='31de::a00:2ff:fe5e:5e5e/96'
MTU=''
NETWORK=''
REMOTE_IPADDR=''
STARTMODE='auto'
USERCONTROL='no 

3. When the network interface should be enabled during operating system initialization, there is a need of following entry:

STARTMODE='auto'

4. After the configuration of selected interfaces, network must be restarted:

service network restart 

IPv6 configuration of domain name resolution (DNS) under Suse Linux

The configuration of domain name resolution in Linux family operating systems resides in /etc/resolv.conf file. When the network interfaces configuration is based on DHCPv6, which broadcasts the DNS IPv6 adresses, the entries in the resolv.conf file are generated automatically. For static configuration there is a need of entering the appropriate IPv6 addresses of DNS servers. Here is a sample resolv.conf configured to operate based on DNS servers with IPv6 addresses:

nameserver 31de::a00:2ff:fe01:0053
nameserver 31de::a00:2ff:fe02:0053