Re: [mosquitto-dev] Socket error on client

[Roger Light <roger@xxxxxxxxxx>]

On Wed, 4 Sep 2019 at 13:34, Greg Troxel <gdt@xxxxxxxxxx> wrote:
>
> Roger Light <roger@xxxxxxxxxx> writes:
>
> > The other option is to use the current `retain_available` option,
> > which if set to false will disconnect clients that publish messages
> > with the retain bit set. I still think it would be useful to have
> > bridge specific options, but this should solve everything for your
> > situation, excepting that clients will still have to know not to send
> > a retain bit.
>
> If that's a spec violation, it would be nice if the comment said that.
> I had the impression that retained message support was required in
> 3.1.1, but I'm really fuzzy on that

I think that it's a grey area for 3.1.1. There are lots of "MUST"
requirements around processing of retain bits which agrees with you,
but then there is "If a Server implementation does not authorize a
PUBLISH to be performed by a Client; it has no way of informing that
Client. It MUST either make a positive acknowledgement, according to
the normal QoS rules, or close the Network Connection [MQTT-3.3.5-2]."
which to me allows denying messages if they have the retain bit set.

Regards,

Roger