IPv6-only networking on WLCG

The use of IPv6 on the general Internet continues to grow. The transition of the Worldwide Large Hadron Collider Computing Grid (WLCG) central and storage services to dual-stack IPv6/IPv4 is progressing well, thus enabling the use of IPv6-only CPU resources as agreed by the WLCG Management Board and presented by us at earlier CHEP conferences. During the last year, the HEPiX IPv6 Working Group has continued to chase and support the transition to dual-stack services. We present the status of the transition and some tests that have been made of IPv6-only CPU showing the successful use of IPv6 protocols in accessing WLCG services. The dual-stack deployment does however result in a networking environment which is more complex than when using just IPv6. The group is investigating the removal of the IPv4 protocol in places. We present the areas where this could be useful together with our future plans.