Yes, Intel network adapters and network connections are tested with and support IPv6.

Intel tests our network adapters with IPv6 traffic using current versions of Microsoft Windows*, Linux*, and FreeBSD*.

This applies to:

EtherExpress™ 10 ISA adapter EtherExpress™ 16 Adapter EtherExpress™ 32 Adapter EtherExpress™ 32N Adapter EtherExpress™ Classic Adapter EtherExpress™ Flash 32 Adapter EtherExpress™ PRO/10 and PRO/10+ ISA adapters EtherExpress™ PRO/10 PCI Adapter EtherExpress™ PRO/10+ PCI Adapter Intel® 10 Gigabit AF DA Dual Port Server Adapter Intel® 10 Gigabit AT Server Adapter Intel® 10 Gigabit CX4 Dual Port Server Adapter Intel® 10 Gigabit XF LR Server Adapter Intel® 10 Gigabit XF SR Dual Port Server Adapter Intel® 10 Gigabit XF SR Server Adapter Intel® Gigabit CT Desktop Adapter Intel® Gigabit ET Dual Port Server Adapter Intel® InBusiness™ 10/100 Adapter Intel® PRO/100 Intelligent Server Adapter Intel® PRO/100 ISA Adapter Intel® PRO/100 S Dual Port Server Adapter Intel® PRO/100 S Server Adapter Intel® PRO/100 Smart Adapter Intel® PRO/100 VE Network Connection Intel® PRO/100 VM Network Connection Intel® PRO/100+ Adapter Intel® PRO/100+ Dual Port Server Adapter Intel® PRO/100+ Management Adapter Intel® PRO/100+ Server Adapter Intel® PRO/1000 CT Network Connection Intel® PRO/1000 F Server Adapter Intel® PRO/1000 Gigabit Server Adapter Intel® PRO/1000 GT Desktop Adapter Intel® PRO/1000 GT Quad Port Server Adapter Intel® PRO/1000 MF Dual Port Server Adapter Intel® PRO/1000 MF Server Adapter Intel® PRO/1000 MF Server Adapter (LX) Intel® PRO/1000 MT Desktop Adapter Intel® PRO/1000 MT Dual Port Server Adapter Intel® PRO/1000 MT Quad Port Server Adapter Intel® PRO/1000 MT Server Adapter Intel® PRO/1000 PF Dual Port Server Adapter Intel® PRO/1000 PF Quad Port Server Adapter Intel® PRO/1000 PF Server Adapter Intel® PRO/1000 PT Desktop Adapter Intel® PRO/1000 PT Dual Port Server Adapter Intel® PRO/1000 PT Quad Port Low Profile Server Adapter Intel® PRO/1000 PT Quad Port Server Adapter Intel® PRO/1000 PT Server Adapter Intel® PRO/1000 T Desktop Adapter Intel® PRO/1000 T Server Adapter Intel® PRO/1000 XF Server Adapter Intel® PRO/1000 XT Low Profile Server Adapter Intel® PRO/1000 XT Server Adapter Intel® PRO/100B Adapter Intel® PRO/10GbE CX4 Server Adapter Intel® PRO/10GbE LR Server Adapter Intel® PRO/10GbE SR Server Adapter