Open Radar

 
Summary:
Enterprise networks use ISATAP to provide IPv6 connectivity across their IPv4 infrastructure.  This becomes especially important when operating from portions of the network that do not or cannot obtain IPv6 connectivity, such as when operating over VPN connections (such as the Cisco VPN client, or the Juniper/Netscreen client) or on a segment of the network where IPv6 is not yet enabled.   Enterprises provide an ISATAP router so that everyone in the enterprise can automatically tunnel to that in order to reach IPv6 servers.   Windows clients have this capability built in, and it just works without any additional configuration on the client.   In MacOS X, the capability is missing.

Steps to Reproduce:
(environment is an enterprise network with an ISATAP router)
1.  Connect Mac to an enterprise network segment that doesn't support IPv6
2.  Connect to an IPv6 service, such as a web site.

Expected Results:
Should immediately connect to the service, using the ISATAP tunnel over the IPv4 network.

Actual Results:
The connection times out.

Regression:
The Mac works just fine when connected to an IPv6-enabled segment, but fails when connected to a segment that is not IPv6-enabled.  Windows computers work just fine in either situation.

Note:  This is a serious problem for mature IPv6-enabled enterprises and mobile computers in that environment.  The mechanism of choice to solve this is ISATAP.  While the logical solution might be to get all network segments IPv6-enabled, this is currently impossible in a number of situations that currently exist, in particular when operating over mainstream VPN clients.  Without ISATAP in MacOS X, these machines can only operate from IPv6-enabled segments.