SOLVED Cannot ping TrueNAS host from VM or Jail via IPv6

[ian.m.taylor]

Hi, sorry if this is the wrong place for this! I am having a weird problem with IPv6 connectivity between my TrueNAS host and its jails/VMs.

Neither my VMs or jails can ping the TrueNAS host over IPv6, but they can over IPv4. Other devices on my network can ping both TrueNAS and the VMs/jails with IPv6 or IPv4, and the host can ping the jails and VMs with IPv6 and IPv4.

To summarize which pings work and which don't:

• IPv4: all work as far as I know
• IPv6
  • VM or jail --> TrueNAS: no
  • VM or jail --> other LAN device: yes
  • VM or jail --> internet: yes
  • other device --> TrueNAS: yes
  • other device --> VM or jail: yes
  • TrueNAS --> VM or jail: yes

Error received when ping fails:

Code:

From transmission (fdxx:xxxx:...) icmp_seq=1 Destination unreachable: Address unreachable
From transmission (fdxx:xxxx:...) icmp_seq=2 Destination unreachable: Address unreachable
From transmission (fdxx:xxxx:...) icmp_seq=3 Destination unreachable: Address unreachable

This is resulting in me not being able to mount SMB shares inside my VMs. The dmesg output from attempting to mount the share is

Code:

[  575.691791] CIFS: Attempting to mount //mytruenashost/transmission/downloads
[  575.691816] No dialect specified on mount. Default has changed to a more secure dialect, SMB2.1 or later (e.g. SMB3), from CIFS (SMB1). To use the less secure SMB1 dialect to access old servers which do not support SMB3 (or SMB2.1) specify vers=1.0 on mount.
[  581.827337] CIFS VFS: Error connecting to socket. Aborting operation.
[  581.827595] CIFS VFS: cifs_mount failed w/return code = -2

I have IPv6 privacy addresses turned on in both host and jail/vm, but I don't think that matters because of all the other pings which do work. Also, the ping from VM to host will fail even if I specify the SLAAC (EUI-64) or DHCPv6-assigned IPv6 address as the source.

Version Details:

• TrueNAS 12.0-U8.1
• Jail FreeBSD version 12.2-RELEASE-p15
• VM is Ubuntu 20.04 Server

Any help would be appreciated! Thank you!


EDIT: The solution ended up being in my network interface configuration.

Previously, I had my physical interface em0 set up with DCHP and autoconfigured IPv6, and em0 selected as the interface for jails and VMs.

Now, I manually created a bridge device bridge0, add em0 to the bridge, and configure bridge0 with DHCP and autoconfigured IPv6. Then use bridge0 as the interface for jails and VMs. Connectivity between jails/VMs and the TrueNAS host works as expected now.