samba - Oct 2018 - Windows Server 2019 / Windows 10 LTSC can't access samba shares on Debian stable 4.5.12

Hello Rowland,
> Stop me if I am wrong (and I often am), but doesn't the
'loopback'
> device do exactly that ? Anything 'lo' receives on its input just
gets
> shoved out of its output, or to put it another way, it just goes
> around in a circle, so how does this work with Samba etc ?  Not saying
> it will not work, trying to understand how it works if it does ;-)
lo is a layer 3 (ip) interface. So everything that speaks ip can talk to
it, if you enable routing on the box. So that means in the past I had 32
publically routed addresses in addition to 10.10.10.1 on lo.

# infra.glanzmann.de:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet 10.10.10.1/32 brd 10.10.10.1 scope global lo:0
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever

# my laptop at home accessing it via vpn:
(x1) [~] traceroute 10.10.10.1
traceroute to 10.10.10.1 (10.10.10.1), 30 hops max, 60 byte packets
 1  192.168.0.3 (192.168.0.3)  1.594 ms  1.677 ms  1.793 ms
 2  10.10.10.1 (10.10.10.1)  15.613 ms  15.698 ms  17.899 ms

Cheers,
        Thomas

On Sat, 13 Oct 2018 10:43:31 +0200
Thomas Glanzmann via samba <samba at lists.samba.org> wrote:
> Hello Rowland,
> 
> > Stop me if I am wrong (and I often am), but doesn't the
'loopback'
> > device do exactly that ? Anything 'lo' receives on its input
just
> > gets shoved out of its output, or to put it another way, it just
> > goes around in a circle, so how does this work with Samba etc ?
> > Not saying it will not work, trying to understand how it works if
> > it does ;-)
> 
> lo is a layer 3 (ip) interface. So everything that speaks ip can talk
> to it, if you enable routing on the box. So that means in the past I
> had 32 publically routed addresses in addition to 10.10.10.1 on lo.
Yes, but it is a special virtual network interface and in, my opinion,
you are 'bending' it to your purposes.
Wouldn't you be better creating proper virtual network interfaces and
leaving 'loopback' to be what it is, a loop. It is however your
computer, so you can do whatever you like and works for you ;-)

Hallo Rowland,
> Yes, but it is a special virtual network interface and in, my opinion,
> you are 'bending' it to your purposes.  Wouldn't you be better
> creating proper virtual network interfaces and leaving 'loopback'
to
> be what it is, a loop. It is however your computer, so you can do
> whatever you like and works for you ;-)
than it is a good thing that you did not saw the rest of the network
configuration on the machine: bonding interfaces, bridges, gre tunnels,
vlan tags, several VPNs, network namespaces, policy based routing for
ipv4 und ipv6, a peer2peer connection and a two routing daemons for ipv4
and ipv6.

Cheers,
        Thomas