IPv6 does not work with gif

[Martti Kuparinen <martti.kuparinen%iki.fi@localhost>]

Hi,

Our NetBSD/amd64 5.0_STABLE firewall (running on Dell PowerEdge R300) has one 
dual-port Intel PRO/1000 card, wm0 is the external connection and wm1 has all 
VLANs on it. The IPv6 connection is normal IPv6-over-IPv4 and we are using gif0 
for that. The hardware looks like this:


wm0 at pci5 dev 0 function 0: Intel PRO/1000 PT (82571EB), rev. 6
wm0: interrupting at ioapic0 pin 16
wm0: PCI-Express bus
wm0: 65536 word (16 address bits) SPI EEPROM
wm0: Ethernet address 00:15:17:79:5b:e2
igphy0 at wm0 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto
wm1 at pci5 dev 0 function 1: Intel PRO/1000 PT (82571EB), rev. 6
wm1: interrupting at ioapic0 pin 17
wm1: PCI-Express bus
wm1: 65536 word (16 address bits) SPI EEPROM
wm1: Ethernet address 00:15:17:79:5b:e3
igphy1 at wm1 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy1: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto


Now, I wanted to replace this card with a quad-port card


wm0 at pci7 dev 0 function 0: Intel PRO/1000 QT (82571EB), rev. 6
wm0: interrupting at ioapic0 pin 16
wm0: PCI-Express bus
wm0: 65536 word (16 address bits) SPI EEPROM
wm0: Ethernet address 00:15:17:90:56:f4
igphy0 at wm0 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto
wm1 at pci7 dev 0 function 1: Intel PRO/1000 QT (82571EB), rev. 6
wm1: interrupting at ioapic0 pin 17
wm1: PCI-Express bus
wm1: 65536 word (16 address bits) SPI EEPROM
wm1: Ethernet address 00:15:17:90:56:f5
igphy1 at wm1 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy1: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto
wm2 at pci8 dev 0 function 0: Intel PRO/1000 QT (82571EB), rev. 6
wm2: interrupting at ioapic0 pin 17
wm2: PCI-Express bus
wm2: 65536 word (16 address bits) SPI EEPROM
wm2: Ethernet address 00:15:17:90:56:f6
igphy2 at wm2 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy2: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto
wm3 at pci8 dev 0 function 1: Intel PRO/1000 QT (82571EB), rev. 6
wm3: interrupting at ioapic0 pin 18
wm3: PCI-Express bus
wm3: 65536 word (16 address bits) SPI EEPROM
wm3: Ethernet address 00:15:17:90:56:f7
igphy3 at wm3 phy 1: Intel IGP01E1000 Gigabit PHY, rev. 0
igphy3: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT, 
1000baseT-FDX, auto


but now our IPv6 tunnel does not work anymore! I can see outgoing echo requests 
and the incoming echo replies with "tcpdump -ni wm0 host OurISP" but I can only 
see the outgoing requests on gif0, there are no replies.

IPv4 works fine with both cards. And there's no hardware checksumming involved.

I had to switch back to the old dual-port card and everything works again.

Any ideas what's going on here? I remember once having problems with the builtin 
Broadcom interfaces (and that's the reason they are disabled in the BIOS and we 
have this PCIe card instead) but this is about two different Intel cards...

Martti