DHCPv6 Client Broken in latest snapshot

darkfire

I found out that there is no IPv6 link local address on my Wan interface, does anyone have an idea why and how can I fix it?

mattund

I have not received an IPv6 address since upgrading to 2.4.4 either. Also on Hyper-V 2016, hn driver in use.

mattund

I found a fix for this on Hyper-V I think...

The only real places Input/output error (aka 5 or EIO) really happen in hn in FreeBSD without printing an error to the system log are in /sys/dev/hyperv/netvsc/if_hn.c

The only thing I noted that's relative to sending packets is the send TCP Checksum Offload, and notably, for IPv6. So, I looked at my ifconfig and suuuure enough,

options=480018<VLAN_MTU,VLAN_HWTAGGING,LINKSTATE,TXCSUM_IPV6> - I had it enabled!

So I took a wild guess, and ran ifconfig hn0 -txcsum6

And ran dhcp6c -c /var/etc/dhcp6c_wan.conf -f hn0 after. I now have IPv6. This might be a start!

EDIT:

I logged a bug report ASAP with upstream FreeBSD just in case there is some substance to what I found: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=231797. In the meantime, disabling all hardware checksum offloading seems to be working perfectly, including across reboot.

bimmerdriver

@mattund It looks like you are onto something. I was in communication with a couple of the developers who reviewed the commit that you referenced, so I sent them an email.

kmo12345

@mattund I tried the steps you posted and immediately saw the IPv6 gateway come back online on the Dashboard.

I rebooted and lost IPv6 again so I went to System / Advanced / Networking and disabled Hardware Checksum Offloading. Looking at the output of ifconfig this definitely removed the IPv4 offloading as well but it seems to give me IPv6 that persists across reboots.

Interestingly, I still don't seem to have any IPv6 for my clients.

EDIT: Looks like the prefix size got reset somehow. I set that properly and I am back in business minus hardware offloading.

mattund

@bimmerdriver Thank you!

@kmo12345
I'm glad it helped

jimp

I was able to reproduce the checksum disable box not actually disabling IPv6 transmit checksums, I opened an issue for that here: https://redmine.pfsense.org/issues/8980

bimmerdriver

@jimp A patch has been posted on https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=231797 for this issue.

jimp

@bimmerdriver said in DHCPv6 Client Broken in latest snapshot:

@jimp A patch has been posted on https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=231797 for this issue.

I opened https://redmine.pfsense.org/issues/9019 to pull in that patch, thanks!

bimmerdriver

@jimp The patch was committed: https://svnweb.freebsd.org/changeset/base/339585. Any idea when there will be a build with it?

jimp

No ETA at the moment, but we'll get to it before -p1.

JeFizz

I was experiencing the same issue. Running the ifconfig hn0 -txcsum6 command while also ticking the option in System / Advanced / Networking did the trick.

Hopefully the patch gets rolled into a build soon. I don't want to forget to set this if I reboot.

bimmerdriver

I updated to the latest snapshot on my test system yesterday. IPv6 is working again. I noticed the update from Renato (https://redmine.pfsense.org/issues/9019) where it says, "FreeBSD r339863 was cherry-picked to RELENG_2_4_4". I guess it's safe to say the fix is in the latest snapshot and it's working.

jimp

Great news! Thanks for testing