Re: IPv6 networking problems in 14.3

From: Karl Denninger <karl_at_denninger.net>
Date: Sun, 14 Sep 2025 17:00:01 UTC
On 9/14/2025 12:38, Chris Ross wrote:
>> On Sep 14, 2025, at 12:29, Karl Denninger<karl@denninger.net> wrote:
>> Rolling this around in my head some more..... what is the underlying interface?
>> I ask because I saw this happen with "re" driver interfaces (both IPv4 and 6) where it would not get an ARP map and thus couldn't see anything at all on the outside - there were enough other screwball things going on with the "re" driver (timeouts and similar) that I tossed that and now run on ix and a couple of SFP+ transceivers which has been entirely-stable (although igb also appears to work as I've gotten my hands on a box with a couple of those and tested that too.)
> In my case it’s an ix.  Connected to a 1gbps switch interface, but an ix interface.  And, the same hardware that was doing this fine a few months ago.
>
> vlan0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1500
>          options=4600703<RXCSUM,TXCSUM,TSO4,TSO6,LRO,RXCSUM_IPV6,TXCSUM_IPV6,MEXTPG>
>          ether a4:53:0e:79:b9:82
>          inet A.B.C.D netmask 0xffffff00 broadcast A.B.C.255
>          inet6 fe80::6e8:e675:f359:3465%vlan0 prefixlen 64 scopeid 0x4
>          groups: vlan
>          vlan: 6 vlanproto: 802.1q vlanpcp: 0 parent interface: ix0
>          media: Ethernet autoselect (1000baseT <full-duplex>)
>          status: active
>          nd6 options=1<PERFORMNUD>
>
> ix0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1500
> 	options=4e53fbb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,WOL_UCAST,WOL_MCAST,WOL_MAGIC,VLAN_HWFILTER,VLAN_HWTSO,RXCSUM_IPV6,TXCSUM_IPV6,HWSTATS,MEXTPG>
>          ether a4:53:0e:79:b9:82
>          media: Ethernet autoselect (1000baseT <full-duplex>)
>          status: active
>          nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>
If you find anything a note back here would be greatly excellent.  I do 
note that per the various notes from long ago I have both tso and lro 
turned off (but I use ipfw, which is where that apparently comes from) 
on the outside interface -- but I doubt that is involved as I did try 
with it on and it didn't change anything.


-- 
Karl Denninger
karl@denninger.net
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