Configuring advanced network services on CentOS 7 can involve several complex steps, especially if you need to support not only traditional IPv4 but also modern IPv6, DHCPv6 for dynamic IP address allocation, and SLAAC for automatic configuration of stateless addresses. This article will provide a comprehensive guide on how to set up these services on CentOS 7.

Prerequisites

• Clean installation of CentOS 7
• Sudo access or root account
• Active network interface

1. Basic Network Interface Configuration

Before diving into configuring IPv6, DHCPv6, and SLAAC, it's important to ensure that the network interface is properly configured for basic network communication.

• Open the configuration file of your network interface using a text editor. We assume the interface is named eth0.

  sudo nano /etc/sysconfig/network-scripts/ifcfg-eth0
  

• Make sure the file contains the following lines for basic IPv4 configuration:

  BOOTPROTO=none
  ONBOOT=yes
  

• For IPv6 settings, add:

  IPV6INIT=yes
  IPV6_AUTOCONF=yes
  

• This will set your interface to use SLAAC for automatic IPv6 address assignment.

2. IPv6 Configuration

CentOS 7 allows configuring IPv6 directly in the network interface configuration file.

• For a static IPv6 address, add the following lines to the configuration file, where xxxx:xxxx:xxxx:xxxx::x is your IPv6 address, and 64 is the prefix length:

  IPV6ADDR=xxxx:xxxx:xxxx:xxxx::x/64
  IPV6_DEFAULTGW=xxxx:xxxx:xxxx:xxxx::1
  

3. DHCPv6 Client Configuration

If your network requires DHCPv6 for IPv6 address allocation, you can configure your system to use the DHCPv6 client.

• Modify the interface configuration file to look like this:

  DHCPV6C=yes
  IPV6INIT=yes
  IPV6_AUTOCONF=no
  

• Restart the network services for the changes to take effect:

  sudo systemctl restart network
  

4. Stateless Autoconfiguration (SLAAC) Setup

SLAAC is already set as the default method for obtaining IPv6 addresses, as mentioned above. To confirm that your interface is using SLAAC:

• Check if autoconfiguration is active:

  ip -6 addr
  

• You should see your IPv6 address assigned to the interface.

5. Additional Configuration and Diagnostics

• Ensure that the firewall allows IPv6 traffic. Adjust firewalld or iptables rules as necessary.

• Use tools like ping6 or traceroute6 for diagnosing network connectivity with IPv6.

• In case of DHCPv6 issues, make sure your DHCP server correctly distributes IPv6 addresses.

 

Configuring advanced network services on CentOS 7 requires careful planning and understanding of network protocols. With proper care and following the correct steps, you can successfully set up IPv6, DHCPv6, and SLAAC on your system, ensuring its compatibility with modern network standards.