illumos gate

This was also submitted to Red Hat, since that's more likely to be where the problem exists.

https://bugzilla.redhat.com/show_bug.cgi?id=1972912

nomad

It looks like this problem is in the IPv6 part of Illumos, not Red Hat.

I configured a test server that has both IPv4 and IPv6 to have SMB and was able to access a test share from it on windows.
I then removed the A record for that host from DNS and tried to access the same share from a different host (so it wouldn't have DNS cached or any existing mounts) and got

"Windows cannot access \\hvfs1\foo

Check the spelling of the name. Otherwise, there might be a problem with your network. ..."

The test server, like all my file servers, is running OmniOS 151038.

SunOS hvfs1 5.11 omnios-r151038-91d640aafa i86pc i386 i86pc

Here's a redacted snoop run on the server host:

; sudo snoop -d aggr0 port 445
Using device aggr0 (promiscuous mode)
[CLIENT - REDACTED] -> [SERVER - REDACTED] SMB C port=64719 
[SERVER - REDACTED] -> [CLIENT - REDACTED] SMB R port=64719 
[CLIENT - REDACTED] -> [SERVER - REDACTED] SMB C port=64719 
[SERVER - REDACTED] -> [CLIENT - REDACTED] SMB R port=64719 
[CLIENT - REDACTED] -> [SERVER - REDACTED] SMB C port=64719 
[SERVER - REDACTED] -> [CLIENT - REDACTED] SMB R port=64719 
[CLIENT - REDACTED] -> [SERVER - REDACTED] SMB C port=64719 
[SERVER - REDACTED] -> [CLIENT - REDACTED] SMB R port=64719 
[CLIENT - REDACTED] -> [SERVER - REDACTED] SMB C port=64719 
[SERVER - REDACTED] -> [CLIENT - REDACTED] SMB R port=64719

nomad

Try sharectl set -p ipv6_enable=true smb then svcadm restart smb/server

Jason King wrote in #note-3:

Try sharectl set -p ipv6_enable=true smb then svcadm restart smb/server

That seems to have resolved the problem. I'll update our internal documentation but that makes me ask if it's documented anywhere? It's been so long since I set up SMB on these servers I honestly don't remember what documentation I used (but I'm pretty sure this wasn't part of it).

thanks for the tip.

Also makes me ask why special enable is required in the first place...

The description of the option is in the smb(4) man page (man -s 4 smb).

My understanding is that it's largely a compatibility issue. Older versions of SMB don't support IPv6, and enabling it will prevent them from connecting. However it's also very likely that the default should probably be revisited. I believe all supported versions of Windows these days (as well as other platforms) should all support SMB versions that can handle IPv6.

Yes, that default should change, along with disabling SMB1 by default (#14097) and updating the man page (#14309).

Gordon Ross wrote in #note-8:

Yes, that default should change, along with disabling SMB1 by default (#14097) and updating the man page (#14309).

Is this ticket sufficient as a request for that change or should I open one with a more direct topic?

Let's just re-use this ticket. Perhaps update the synopsis? (SMB server should enable IPv6 by default)

Gordon Ross wrote in #note-10:

Let's just re-use this ticket. Perhaps update the synopsis? (SMB server should enable IPv6 by default)

I don't appear to have the permissions/ability to make any changes in that part of the ticket. Not surprising, really.