PittNet (Wired): Enabling and Disabling Internet Protocol Version 6 (IPv6) on PCs


The University has begun enabling support for Internet Protocol Version 6 (IPv6), which is one of two versions of the Internet Protocol that is used to carry Internet traffic. Every device that is connected to a network and uses the Internet Protocol for communication acquires a unique number known as an IP address.   

The number of available IPv4 addresses will soon be exhausted. In many parts of the world, they have already been exhausted.

IPv6 solves the shortage of IP addresses. The length of an IPv6 address is 128 bits (allowing for approximately 340 trillion trillion trillion addresses) compared to 32 bits in IPv4 (allowing for about 4.3 billion unique addresses).

Most Internet traffic today uses IPv4. However, IPv6 Internet traffic is growing rapidly. All key components of the University network infrastructure support both IPv4 and IPv6 traffic.

Frequently Asked Questions

Frequently Asked Questions

What does IPv6 mean to me?

IPv6 has a number of features of interest to IT professionals, including new extension headers and new ICMP (v6) message types. For the majority of users, there is no measurable performance advantage between connecting to web sites and other Internet resources using IPv4 versus IPv6. However, in the years to come, the exhaustion of available IPv4 address space will mean that some sites and systems on the Internet will only be accessible by using IPv6. IPv6-enabled systems on the University network will have no problems communicating with these sites.

How do I know if IPv6 is enabled on my computer?

Most major PC and mobile/tablet operating systems support IPv6 by default, and many will prefer to use IPv6 when it is available. You can see if your device has IPv6 enabled by going to the web site test-ipv6.com, which runs a quick check and reports whether or not your system is using IPv6.  

How can I tell if PittNet has IPv6 transport available to my machine?

The IPv6 test report that you will receive by going to http://test-ipv6.com will tell you whether or not your system is connected to a PittNet virtual local area network (VLAN) that supports IPv6.

VLANs are allocations of network address space that have been configured to support a related-group of machines, such as a PCs in a department office or a lab. Your department’s system administrator should be able to tell you if your network connection is on an IPv6-enabled VLAN.

Note: all of Wireless-PittNet supports IPv6.

How do I enable or disable IPv6 on my computer?

Some devices and operating systems might not have IPv6 enabled by default. Refer to the Enabling and Disabling IPv6 page for instructions that explain how to turn on and turn off IPv6 on your device.

Will Pitt be turning off IPv4?

There are no plans to turn off IPv4 at this time. IPv4 will be continue to be supported on the University’s network for some time.

Does CSSD support translation between IPv4 and IPv6?

No. CSSD currently supports IPv6 in the dual stack host method. This means that end nodes must be IPv4 and/or IPv6 natively.

Additional Technical Details

Additional Technical Details

IPv6 at Pitt (PowerPoint Presentation)

IPv6 in Workstation and Server Zones 

Workstation Zones

All address allocations for workstation zones will be dynamic via DHCP version 6 (DHCPv6) with DDNS proxy via DHCPv6. This means that you will not contact the Technology Help Desk to request an IPv6 name or address in a workstation zone. Instead, it will automatically be assigned for machines that request one. The name you request in your DHCPv6 request will be granted in the default zone on that subnet, if available. If it is not available, another name from a CSSD template will be assigned.

Server Zones

For the time being, Computing Services and Systems Development will only support static names and static IPv6 addresses in a similar mechanism to how IPv4 names and addresses are allocated now. This practice will help ensure that servers have consistent names, which is important for those who are trying to connect to them. It is up to the user whether the machine has the same name for IPv4 and IPv6 resolution. If you would like the machine to have the same name for IPv4 and IPv6 resolution, you must validate that your applications work with IPv6 transport.   

Bringing Up IPv6 on a Server

IPv6 was made to be “downward compatible” with IPv4. This means that if you have an application that is using an IPv4 transport, it should also work on an IPv6 transport. However, there are scenarios that can complicate this. For example, you may have IPv4 ACLs or you may have IPv4 references inside the app that are being done by IP address. For these reasons, it is important to thoroughly test IPv6 when implementing it on servers.

Bringing up IPv6 on a server involves the following steps and testing procedures:

  1. First, make sure to disable IPv6 transport for all target servers.
  2. Open a ticket with CSSD to enable IPv6 for the subnet where the affected servers reside. CSSD will enable a pre-assigned IPv6 subnet at the router level and will assign overhead firewall rules for the zone.
  3. Work with CSSD to obtain static IPv6 addresses for all affected servers. The assigned IPv6 domain names will be different than the existing IPv4 domain names. IPv6-enabled servers that join the UNIV (univ.pitt.edu) domain will register the IPv6 domain name with Active Directory. This may cause problems with applications on the server that do not support IPv6.
  4. CSSD will provide an IPv6 router address.
  5. Go to firewall.pitt.edu to request the proper IPv6 rules for the application or service that will be hosted on the affected servers.
  6. Enable IPv6 on the affected servers.
  7. Test all server applications and functions with IPv6 transport enabled.
  8. If tests are successful, work with CSSD on registering the same domain name for both IPv4 (A-record) and IPv6 (AAA-record) for all affected servers.