# MQTT 5.0: broker is active messages are not displaying

**URL:** <https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947>\
**Category:** Broker management and monitoring\
**Created:** [March 9, 2024, 7:55pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947 "2024-03-09T19:55:00Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![preWarp](https://avatars.discourse-cdn.com/v4/letter/p/ee7513/32.png) [@preWarp](https://forum.cedalo.com/u/preWarp)\
**Post date:** [March 9, 2024, 7:55pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/1 "2024-03-09T19:55:00Z")

</div>

I am using two desktop computers with Ubuntu and Mint Linux. Each have mosquito 5 installed and package mosquito-clients.

My logs show that every time I use mosquitto\_sub and \_pub, the corresponding ip address of the other machine, and username/password; my logs show successful connections.

However I am not seeing any messages with which ever machine is subscribing to whichever machine is publishing.

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<div class="post-metadata">

**Author:** ![Tizian](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.cedalo.com/tizian/32/33_2.png) [@Tizian](https://forum.cedalo.com/u/Tizian)\
**Post date:** [March 11, 2024, 8:55am UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/2 "2024-03-11T08:55:00Z")

</div>

Hi preWarp,

Let me see if we can find the reason for this 🙂  
How are you expecting to see the messages send?  
This is only possible when you also subscribe at the same time to that same topic.

If you are already doing that, what is your setup like? Sometimes the assigned ACLs to used client credentials are not allowing a client to either publish or subscribe to a topic. This won´t show in the logs.

If that is also not the case, could you post your config and your pub/sub statements?

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<div class="post-metadata">

**Author:** ![preWarp](https://avatars.discourse-cdn.com/v4/letter/p/ee7513/32.png) [@preWarp](https://forum.cedalo.com/u/preWarp)\
**Post date:** [March 11, 2024, 2:17pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/3 "2024-03-11T14:17:43Z")

</div>

Thanks for offering to help.

Here is my (1) config file, (2) my acls file, (3) example password file, and (4) my logs.

My sub and pub statements are as follows:

mosquitto\_sub -h 192.168.1.106 -u roger -P xyzexample’ -t MQBT1

mosquitto\_pub -h 192.168.1.115 -u roger -P xyzexample’ -t MQBT1 -m “hello”

* * *

## (1) Mosquito.conf

# Config file for mosquitto

# 

# See mosquitto.conf(5) for more information.

# 

# Default values are shown, uncomment to change.

# 

# Use the # character to indicate a comment, but only if it is the

# very first character on the line.

# =================================================================

# General configuration

# =================================================================

# Use per listener security settings.

# 

# It is recommended this option be set before any other options.

# 

# If this option is set to true, then all authentication and access control

# options are controlled on a per listener basis. The following options are

# affected:

# 

# password\_file acl\_file psk\_file auth\_plugin auth\_opt\_\* allow\_anonymous

# auto\_id\_prefix allow\_zero\_length\_clientid

# 

# Note that if set to true, then a durable client (i.e. with clean session set

# to false) that has disconnected will use the ACL settings defined for the

# listener that it was most recently connected to.

# 

# The default behaviour is for this to be set to false, which maintains the

# setting behaviour from previous versions of mosquitto.

#per\_listener\_settings false

# This option controls whether a client is allowed to connect with a zero

# length client id or not. This option only affects clients using MQTT v3.1.1

# and later. If set to false, clients connecting with a zero length client id

# are disconnected. If set to true, clients will be allocated a client id by

# the broker. This means it is only useful for clients with clean session set

# to true.

#allow\_zero\_length\_clientid true

# If allow\_zero\_length\_clientid is true, this option allows you to set a prefix

# to automatically generated client ids to aid visibility in logs.

# Defaults to ‘auto-’

#auto\_id\_prefix auto-

# This option affects the scenario when a client subscribes to a topic that has

# retained messages. It is possible that the client that published the retained

# message to the topic had access at the time they published, but that access

# has been subsequently removed. If check\_retain\_source is set to true, the

# default, the source of a retained message will be checked for access rights

# before it is republished. When set to false, no check will be made and the

# retained message will always be published. This affects all listeners.

#check\_retain\_source true

# QoS 1 and 2 messages will be allowed inflight per client until this limit

# is exceeded. Defaults to 0. (No maximum)

# See also max\_inflight\_messages

#max\_inflight\_bytes 0

# The maximum number of QoS 1 and 2 messages currently inflight per

# client.

# This includes messages that are partway through handshakes and

# those that are being retried. Defaults to 20. Set to 0 for no

# maximum. Setting to 1 will guarantee in-order delivery of QoS 1

# and 2 messages.

#max\_inflight\_messages 20

# For MQTT v5 clients, it is possible to have the server send a "server

# keepalive" value that will override the keepalive value set by the client.

# This is intended to be used as a mechanism to say that the server will

# disconnect the client earlier than it anticipated, and that the client should

# use the new keepalive value. The max\_keepalive option allows you to specify

# that clients may only connect with keepalive less than or equal to this

# value, otherwise they will be sent a server keepalive telling them to use

# max\_keepalive. This only applies to MQTT v5 clients. The maximum value

# allowable is 65535. Do not set below 10.

#max\_keepalive 65535

# For MQTT v5 clients, it is possible to have the server send a "maximum packet

# size" value that will instruct the client it will not accept MQTT packets

# with size greater than max\_packet\_size bytes. This applies to the full MQTT

# packet, not just the payload. Setting this option to a positive value will

# set the maximum packet size to that number of bytes. If a client sends a

# packet which is larger than this value, it will be disconnected. This applies

# to all clients regardless of the protocol version they are using, but v3.1.1

# and earlier clients will of course not have received the maximum packet size

# information. Defaults to no limit. Setting below 20 bytes is forbidden

# because it is likely to interfere with ordinary client operation, even with

# very small payloads.

#max\_packet\_size 0

# QoS 1 and 2 messages above those currently in-flight will be queued per

# client until this limit is exceeded. Defaults to 0. (No maximum)

# See also max\_queued\_messages.

# If both max\_queued\_messages and max\_queued\_bytes are specified, packets will

# be queued until the first limit is reached.

#max\_queued\_bytes 0

# Set the maximum QoS supported. Clients publishing at a QoS higher than

# specified here will be disconnected.

#max\_qos 2

# The maximum number of QoS 1 and 2 messages to hold in a queue per client

# above those that are currently in-flight. Defaults to 1000. Set

# to 0 for no maximum (not recommended).

# See also queue\_qos0\_messages.

# See also max\_queued\_bytes.

#max\_queued\_messages 1000

# 

# This option sets the maximum number of heap memory bytes that the broker will

# allocate, and hence sets a hard limit on memory use by the broker. Memory

# requests that exceed this value will be denied. The effect will vary

# depending on what has been denied. If an incoming message is being processed,

# then the message will be dropped and the publishing client will be

# disconnected. If an outgoing message is being sent, then the individual

# message will be dropped and the receiving client will be disconnected.

# Defaults to no limit.

#memory\_limit 0

# This option sets the maximum publish payload size that the broker will allow.

# Received messages that exceed this size will not be accepted by the broker.

# The default value is 0, which means that all valid MQTT messages are

# accepted. MQTT imposes a maximum payload size of 268435455 bytes.

#message\_size\_limit 0

# This option allows persistent clients (those with clean session set to false)

# to be removed if they do not reconnect within a certain time frame.

# 

# This is a non-standard option in MQTT V3.1 but allowed in MQTT v3.1.1.

# 

# Badly designed clients may set clean session to false whilst using a randomly

# generated client id. This leads to persistent clients that will never

# reconnect. This option allows these clients to be removed.

# 

# The expiration period should be an integer followed by one of h d w m y for

# hour, day, week, month and year respectively. For example

# 

# persistent\_client\_expiration 2m

# persistent\_client\_expiration 14d

# persistent\_client\_expiration 1y

# 

# The default if not set is to never expire persistent clients.

#persistent\_client\_expiration

# Write process id to a file. Default is a blank string which means

# a pid file shouldn’t be written.

# This should be set to /var/run/mosquitto/mosquitto.pid if mosquitto is

# being run automatically on boot with an init script and

# start-stop-daemon or similar.

#pid\_file

# Set to true to queue messages with QoS 0 when a persistent client is

# disconnected. These messages are included in the limit imposed by

# max\_queued\_messages and max\_queued\_bytes

# Defaults to false.

# This is a non-standard option for the MQTT v3.1 spec but is allowed in

# v3.1.1.

#queue\_qos0\_messages false

# Set to false to disable retained message support. If a client publishes a

# message with the retain bit set, it will be disconnected if this is set to

# false.

#retain\_available true

# Disable Nagle’s algorithm on client sockets. This has the effect of reducing

# latency of individual messages at the potential cost of increasing the number

# of packets being sent.

#set\_tcp\_nodelay false

# Time in seconds between updates of the $SYS tree.

# Set to 0 to disable the publishing of the $SYS tree.

#sys\_interval 10

# The MQTT specification requires that the QoS of a message delivered to a

# subscriber is never upgraded to match the QoS of the subscription. Enabling

# this option changes this behaviour. If upgrade\_outgoing\_qos is set true,

# messages sent to a subscriber will always match the QoS of its subscription.

# This is a non-standard option explicitly disallowed by the spec.

#upgrade\_outgoing\_qos false

# When run as root, drop privileges to this user and its primary

# group.

# Set to root to stay as root, but this is not recommended.

# If set to “mosquitto”, or left unset, and the “mosquitto” user does not exist

# then it will drop privileges to the “nobody” user instead.

# If run as a non-root user, this setting has no effect.

# Note that on Windows this has no effect and so mosquitto should be started by

# the user you wish it to run as.

#user mosquitto

# =================================================================

# Listeners

# =================================================================

# Listen on a port/ip address combination. By using this variable

# multiple times, mosquitto can listen on more than one port. If

# this variable is used and neither bind\_address nor port given,

# then the default listener will not be started.

# The port number to listen on must be given. Optionally, an ip

# address or host name may be supplied as a second argument. In

# this case, mosquitto will attempt to bind the listener to that

# address and so restrict access to the associated network and

# interface. By default, mosquitto will listen on all interfaces.

# Note that for a websockets listener it is not possible to bind to a host

# name.

# 

# On systems that support Unix Domain Sockets, it is also possible

# to create a # Unix socket rather than opening a TCP socket. In

# this case, the port number should be set to 0 and a unix socket

# path must be provided, e.g.

# listener 0 /tmp/mosquitto.sock

# 

# listener port-number [ip address/host name/unix socket path]

listener 1883

# By default, a listener will attempt to listen on all supported IP protocol

# versions. If you do not have an IPv4 or IPv6 interface you may wish to

# disable support for either of those protocol versions. In particular, note

# that due to the limitations of the websockets library, it will only ever

# attempt to open IPv6 sockets if IPv6 support is compiled in, and so will fail

# if IPv6 is not available.

# 

# Set to `ipv4` to force the listener to only use IPv4, or set to `ipv6` to

# force the listener to only use IPv6. If you want support for both IPv4 and

# IPv6, then do not use the socket\_domain option.

# 

#socket\_domain

# Bind the listener to a specific interface. This is similar to

# the [ip address/host name] part of the listener definition, but is useful

# when an interface has multiple addresses or the address may change. If used

# with the [ip address/host name] part of the listener definition, then the

# bind\_interface option will take priority.

# Not available on Windows.

# 

# Example: bind\_interface eth0

#bind\_interface wlp1s0

# When a listener is using the websockets protocol, it is possible to serve

# http data as well. Set http\_dir to a directory which contains the files you

# wish to serve. If this option is not specified, then no normal http

# connections will be possible.

#http\_dir

# The maximum number of client connections to allow. This is

# a per listener setting.

# Default is -1, which means unlimited connections.

# Note that other process limits mean that unlimited connections

# are not really possible. Typically the default maximum number of

# connections possible is around 1024.

#max\_connections -1

# The listener can be restricted to operating within a topic hierarchy using

# the mount\_point option. This is achieved be prefixing the mount\_point string

# to all topics for any clients connected to this listener. This prefixing only

# happens internally to the broker; the client will not see the prefix.

#mount\_point

# Choose the protocol to use when listening.

# This can be either mqtt or websockets.

# Certificate based TLS may be used with websockets, except that only the

# cafile, certfile, keyfile, ciphers, and ciphers\_tls13 options are supported.

#protocol mqtt

# Set use\_username\_as\_clientid to true to replace the clientid that a client

# connected with with its username. This allows authentication to be tied to

# the clientid, which means that it is possible to prevent one client

# disconnecting another by using the same clientid.

# If a client connects with no username it will be disconnected as not

# authorised when this option is set to true.

# Do not use in conjunction with clientid\_prefixes.

# See also use\_identity\_as\_username.

#use\_username\_as\_clientid

# Change the websockets headers size. This is a global option, it is not

# possible to set per listener. This option sets the size of the buffer used in

# the libwebsockets library when reading HTTP headers. If you are passing large

# header data such as cookies then you may need to increase this value. If left

# unset, or set to 0, then the default of 1024 bytes will be used.

#websockets\_headers\_size

# -----------------------------------------------------------------

# Certificate based SSL/TLS support

# -----------------------------------------------------------------

# The following options can be used to enable certificate based SSL/TLS support

# for this listener. Note that the recommended port for MQTT over TLS is 8883,

# but this must be set manually.

# 

# See also the mosquitto-tls man page and the "Pre-shared-key based SSL/TLS

# support" section. Only one of certificate or PSK encryption support can be

# enabled for any listener.

# Both of certfile and keyfile must be defined to enable certificate based

# TLS encryption.

# Path to the PEM encoded server certificate.

#certfile

# Path to the PEM encoded keyfile.

#keyfile

# If you wish to control which encryption ciphers are used, use the ciphers

# option. The list of available ciphers can be optained using the "openssl

# ciphers" command and should be provided in the same format as the output of

# that command. This applies to TLS 1.2 and earlier versions only. Use

# ciphers\_tls1.3 for TLS v1.3.

#ciphers

# Choose which TLS v1.3 ciphersuites are used for this listener.

# Defaults to “TLS\_AES\_256\_GCM\_SHA384:TLS\_CHACHA20\_POLY1305\_SHA256:TLS\_AES\_128\_GCM\_SHA256”

#ciphers\_tls1.3

# If you have require\_certificate set to true, you can create a certificate

# revocation list file to revoke access to particular client certificates. If

# you have done this, use crlfile to point to the PEM encoded revocation file.

#crlfile

# To allow the use of ephemeral DH key exchange, which provides forward

# security, the listener must load DH parameters. This can be specified with

# the dhparamfile option. The dhparamfile can be generated with the command

# e.g. “openssl dhparam -out dhparam.pem 2048”

#dhparamfile

# By default an TLS enabled listener will operate in a similar fashion to a

# https enabled web server, in that the server has a certificate signed by a CA

# and the client will verify that it is a trusted certificate. The overall aim

# is encryption of the network traffic. By setting require\_certificate to true,

# the client must provide a valid certificate in order for the network

# connection to proceed. This allows access to the broker to be controlled

# outside of the mechanisms provided by MQTT.

#require\_certificate false

# cafile and capath define methods of accessing the PEM encoded

# Certificate Authority certificates that will be considered trusted when

# checking incoming client certificates.

# cafile defines the path to a file containing the CA certificates.

# capath defines a directory that will be searched for files

# containing the CA certificates. For capath to work correctly, the

# certificate files must have “.crt” as the file ending and you must run

# “openssl rehash ” each time you add/remove a certificate.

#cafile

#capath

# If require\_certificate is true, you may set use\_identity\_as\_username to true

# to use the CN value from the client certificate as a username. If this is

# true, the password\_file option will not be used for this listener.

#use\_identity\_as\_username false

# -----------------------------------------------------------------

# Pre-shared-key based SSL/TLS support

# -----------------------------------------------------------------

# The following options can be used to enable PSK based SSL/TLS support for

# this listener. Note that the recommended port for MQTT over TLS is 8883, but

# this must be set manually.

# 

# See also the mosquitto-tls man page and the "Certificate based SSL/TLS

# support" section. Only one of certificate or PSK encryption support can be

# enabled for any listener.

# The psk\_hint option enables pre-shared-key support for this listener and also

# acts as an identifier for this listener. The hint is sent to clients and may

# be used locally to aid authentication. The hint is a free form string that

# doesn’t have much meaning in itself, so feel free to be creative.

# If this option is provided, see psk\_file to define the pre-shared keys to be

# used or create a security plugin to handle them.

#psk\_hint

# When using PSK, the encryption ciphers used will be chosen from the list of

# available PSK ciphers. If you want to control which ciphers are available,

# use the “ciphers” option. The list of available ciphers can be optained

# using the “openssl ciphers” command and should be provided in the same format

# as the output of that command.

#ciphers

# Set use\_identity\_as\_username to have the psk identity sent by the client used

# as its username. Authentication will be carried out using the PSK rather than

# the MQTT username/password and so password\_file will not be used for this

# listener.

#use\_identity\_as\_username false

# =================================================================

# Persistence

# =================================================================

# If persistence is enabled, save the in-memory database to disk

# every autosave\_interval seconds. If set to 0, the persistence

# database will only be written when mosquitto exits. See also

# autosave\_on\_changes.

# Note that writing of the persistence database can be forced by

# sending mosquitto a SIGUSR1 signal.

#autosave\_interval 1800

# If true, mosquitto will count the number of subscription changes, retained

# messages received and queued messages and if the total exceeds

# autosave\_interval then the in-memory database will be saved to disk.

# If false, mosquitto will save the in-memory database to disk by treating

# autosave\_interval as a time in seconds.

#autosave\_on\_changes false

# Save persistent message data to disk (true/false).

# This saves information about all messages, including

# subscriptions, currently in-flight messages and retained

# messages.

# retained\_persistence is a synonym for this option.

#persistence false

# The filename to use for the persistent database, not including

# the path.

#persistence\_file mosquitto.db

# Location for persistent database.

# Default is an empty string (current directory).

# Set to e.g. /var/lib/mosquitto if running as a proper service on Linux or

# similar.

#persistence\_location

# =================================================================

# Logging

# =================================================================

# Places to log to. Use multiple log\_dest lines for multiple

# logging destinations.

# Possible destinations are: stdout stderr syslog topic file dlt

# 

# stdout and stderr log to the console on the named output.

# 

# syslog uses the userspace syslog facility which usually ends up

# in /var/log/messages or similar.

# 

# topic logs to the broker topic ‘$SYS/broker/log/’,

# where severity is one of D, E, W, N, I, M which are debug, error,

# warning, notice, information and message. Message type severity is used by

# the subscribe/unsubscribe log\_types and publishes log messages to

# $SYS/broker/log/M/susbcribe or $SYS/broker/log/M/unsubscribe.

# 

# The file destination requires an additional parameter which is the file to be

# logged to, e.g. “log\_dest file /var/log/mosquitto.log”. The file will be

# closed and reopened when the broker receives a HUP signal. Only a single file

# destination may be configured.

# 

# The dlt destination is for the automotive `Diagnostic Log and Trace` tool.

# This requires that Mosquitto has been compiled with DLT support.

# 

# Note that if the broker is running as a Windows service it will default to

# “log\_dest none” and neither stdout nor stderr logging is available.

# Use “log\_dest none” if you wish to disable logging.

#log\_dest stderr

# Types of messages to log. Use multiple log\_type lines for logging

# multiple types of messages.

# Possible types are: debug, error, warning, notice, information,

# none, subscribe, unsubscribe, websockets, all.

# Note that debug type messages are for decoding the incoming/outgoing

# network packets. They are not logged in “topics”.

#log\_type error

#log\_type warning

#log\_type notice

#log\_type information

# If set to true, client connection and disconnection messages will be included

# in the log.

connection\_messages true

# If using syslog logging (not on Windows), messages will be logged to the

# “daemon” facility by default. Use the log\_facility option to choose which of

# local0 to local7 to log to instead. The option value should be an integer

# value, e.g. “log\_facility 5” to use local5.

#log\_facility

# If set to true, add a timestamp value to each log message.

log\_timestamp true

# Set the format of the log timestamp. If left unset, this is the number of

# seconds since the Unix epoch.

# This is a free text string which will be passed to the strftime function. To

# get an ISO 8601 datetime, for example:

log\_timestamp\_format %Y-%m-%dT%H:%M:%S

#log\_timestamp\_format

# Change the websockets logging level. This is a global option, it is not

# possible to set per listener. This is an integer that is interpreted by

# libwebsockets as a bit mask for its lws\_log\_levels enum. See the

# libwebsockets documentation for more details. “log\_type websockets” must also

# be enabled.

#websockets\_log\_level 0

# =================================================================

# Security

# =================================================================

# If set, only clients that have a matching prefix on their

# clientid will be allowed to connect to the broker. By default,

# all clients may connect.

# For example, setting “secure-” here would mean a client "secure-

# client" could connect but another with clientid “mqtt” couldn’t.

#clientid\_prefixes

# Boolean value that determines whether clients that connect

# without providing a username are allowed to connect. If set to

# false then a password file should be created (see the

# password\_file option) to control authenticated client access.

# 

# Defaults to false, unless there are no listeners defined in the configuration

# file, in which case it is set to true, but connections are only allowed from

# the local machine.

allow\_anonymous false

# -----------------------------------------------------------------

# Default authentication and topic access control

# -----------------------------------------------------------------

# Control access to the broker using a password file. This file can be

# generated using the mosquitto\_passwd utility. If TLS support is not compiled

# into mosquitto (it is recommended that TLS support should be included) then

# plain text passwords are used, in which case the file should be a text file

# with lines in the format:

# username:password

# The password (and colon) may be omitted if desired, although this

# offers very little in the way of security.

# 

# See the TLS client require\_certificate and use\_identity\_as\_username options

# for alternative authentication options. If an auth\_plugin is used as well as

# password\_file, the auth\_plugin check will be made first.

password\_file /etc/mosquitto/secret.txt

# Access may also be controlled using a pre-shared-key file. This requires

# TLS-PSK support and a listener configured to use it. The file should be text

# lines in the format:

# identity:key

# The key should be in hexadecimal format without a leading “0x”.

# If an auth\_plugin is used as well, the auth\_plugin check will be made first.

#psk\_file

# Control access to topics on the broker using an access control list

# file. If this parameter is defined then only the topics listed will

# have access.

# If the first character of a line of the ACL file is a # it is treated as a

# comment.

# Topic access is added with lines of the format:

# 

# topic [read|write|readwrite|deny]

# 

# The access type is controlled using “read”, “write”, “readwrite” or “deny”.

# This parameter is optional (unless contains a space character) - if

# not given then the access is read/write. can contain the + or

# wildcards as in subscriptions.

# 

# The “deny” option can used to explicity deny access to a topic that would

# otherwise be granted by a broader read/write/readwrite statement. Any “deny”

# topics are handled before topics that grant read/write access.

# 

# The first set of topics are applied to anonymous clients, assuming

# allow\_anonymous is true. User specific topic ACLs are added after a

# user line as follows:

# 

# user

# 

# The username referred to here is the same as in password\_file. It is

# not the clientid.

# 

# 

# If is also possible to define ACLs based on pattern substitution within the

# topic. The patterns available for substition are:

# 

# %c to match the client id of the client

# %u to match the username of the client

# 

# The substitution pattern must be the only text for that level of hierarchy.

# 

# The form is the same as for the topic keyword, but using pattern as the

# keyword.

# Pattern ACLs apply to all users even if the “user” keyword has previously

# been given.

# 

# If using bridges with usernames and ACLs, connection messages can be allowed

# with the following pattern:

# pattern write $SYS/broker/connection/%c/state

# 

# pattern [read|write|readwrite]

# 

# Example:

# 

# pattern write sensor/%u/data

# 

# If an auth\_plugin is used as well as acl\_file, the auth\_plugin check will be

# made first.

acl\_file /etc/mosquitto/acls.txt

# -----------------------------------------------------------------

# External authentication and topic access plugin options

# -----------------------------------------------------------------

# External authentication and access control can be supported with the

# auth\_plugin option. This is a path to a loadable plugin. See also the

# auth\_opt\_\* options described below.

# 

# The auth\_plugin option can be specified multiple times to load multiple

# plugins. The plugins will be processed in the order that they are specified

# here. If the auth\_plugin option is specified alongside either of

# password\_file or acl\_file then the plugin checks will be made first.

# 

#auth\_plugin

# If the auth\_plugin option above is used, define options to pass to the

# plugin here as described by the plugin instructions. All options named

# using the format auth\_opt\_\* will be passed to the plugin, for example:

# 

# auth\_opt\_db\_host

# auth\_opt\_db\_port

# auth\_opt\_db\_username

# auth\_opt\_db\_password

# =================================================================

# Bridges

the hostname of this computer.

# This replaces the old “clientid” option to avoid confusion. “clientid”

# remains valid for the time being.

#remote\_clientid

# Set the password to use when connecting to a broker that requires

# authentication. This option is only used if remote\_username is also set.

# This replaces the old “password” option to avoid confusion. “password”

# remains valid for the time being.

#remote\_password

# Set the username to use when connecting to a broker that requires

# restart\_timeout 10 30

# 

# Defaults to jitter with a base of 5 and cap of 30

#restart\_timeout 5 30

# If the bridge has more than one address given in the address/addresses

# configuration, the round\_robin option defines the behaviour of the bridge on

# a failure of the bridge connection. If round\_robin is false, the default

# value, then the first address is treated as the main bridge connection. If

# the connection fails, the other secondary addresses will be attempted in

# turn. Whilst connected to a secondary bridge, the bridge will periodically

# attempt to reconnect to the main bridge until successful.

# If round\_robin is true, then all addresses are treated as equals. If a

# connection fails, the next address will be tried and if successful will

# remain connected until it fails

* * *

## (2) acls file

topic readwrite MQBT1  
user rei

* * *

## (3) password file

roger:$6$clQ4Ocu312S0qWgl$Cv2wUxgEN73c6C6jlBkswqR4AkHsvDLWvtEXZZ8NpsBLgP1WAo/qA+WXcmEN/mjDNgdUwcxRAveqNMs2xUVQYA==

* * *

## (4) Log file

2024-03-11T08:04:07: mosquitto version 2.0.11 starting

2024-03-11T08:04:07: Config loaded from /etc/mosquitto/mosquitto.conf.

2024-03-11T08:04:07: Opening ipv4 listen socket on port 1883.

2024-03-11T08:04:07: Opening ipv6 listen socket on port 1883.

2024-03-11T08:04:07: mosquitto version 2.0.11 running

2024-03-11T08:12:19: New connection from 192.168.1.106:42466 on port 1883.

2024-03-11T08:12:19: New client connected from 192.168.1.106:42466 as auto-765394D0-A846-9ACA-02F6-2E21DD6EF22B (p2, c1, k60, u’rei’).

2024-03-11T08:12:19: Client auto-765394D0-A846-9ACA-02F6-2E21DD6EF22B disconnected.

---

<div class="post-metadata">

**Author:** ![Tizian](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.cedalo.com/tizian/32/33_2.png) [@Tizian](https://forum.cedalo.com/u/Tizian)\
**Post date:** [March 11, 2024, 2:40pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/4 "2024-03-11T14:40:18Z")

</div>

Could you please make this a bit more readable? 🙃 I won´t be able to find out much like this.

---

<div class="post-metadata">

**Author:** ![preWarp](https://avatars.discourse-cdn.com/v4/letter/p/ee7513/32.png) [@preWarp](https://forum.cedalo.com/u/preWarp)\
**Post date:** [March 11, 2024, 4:47pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/5 "2024-03-11T16:47:08Z")

</div>

I shortened my configuration file to only the areas I had uncommented for use with configuring the broker.

Here is my (1) sub/pub statements, (2) config file, (3) my acls file, (4) example password file, and (5) my logs.

* * *

## (1) sub/pub statements

mosquitto\_sub -h 192.168.1.106 -u roger -P xyzexample’ -t MQBT1

mosquitto\_pub -h 192.168.1.115 -u roger -P xyzexample’ -t MQBT1 -m “hello”

* * *

## (2) Mosquito.conf

Config file for mosquitto

See mosquitto.conf(5) for more information.  
Default values are shown, uncomment to change.  
Use the # character to indicate a comment, but only if it is the  
very first character on the line.

# ============================================== General configuration

==============================================  
**LISTENERS**

==============================================  
On systems that support Unix Domain Sockets, it is also possible  
to create a # Unix socket rather than opening a TCP socket. In  
this case, the port number should be set to 0 and a unix socket  
path must be provided, e.g.  
listener 0 /tmp/mosquitto.sock  
listener port-number [ip address/host name/unix socket path]

listener 1883

==============================================  
Logging

==============================================  
Places to log to. Use multiple log\_dest lines for multiple  
logging destinations.  
If set to true, client connection and disconnection messages will be included  
in the log.

connection\_messages true

log\_timestamp true  
Set the format of the log timestamp. If left unset, this is the number of  
seconds since the Unix epoch.  
This is a free text string which will be passed to the strftime function. To  
get an ISO 8601 datetime, for example:

log\_timestamp\_format %Y-%m-%dT%H:%M:%S

===========================================  
Security

===========================================  
If set, only clients that have a matching prefix on their  
clientid will be allowed to connect to the broker. By default,  
all clients may connect.  
For example, setting “secure-” here would mean a client “secure-  
client” could connect but another with clientid “mqtt” couldn’t.

allow\_anonymous false

===========================================  
Default authentication and topic access control

===========================================  
Control access to the broker using a password file. This file can be  
generated using the mosquitto\_passwd utility.

password\_file /etc/mosquitto/passwordfile\_example.txt

acl\_file /etc/mosquitto/acls.txt

(3) acls file

topic readwrite MQBT1  
user rei

(4) password file

roger:$6$clQ4Ocu312S0qWgl$Cv2wUxgEN73c6C6jlBkswqR4AkHsvDLWvtEXZZ8NpsBLgP1WAo/qA+WXcmEN/mjDNgdUwcxRAveqNMs2xUVQYA==

(5) Log file

2024-03-11T08:04:07: mosquitto version 2.0.11 starting

2024-03-11T08:04:07: Config loaded from /etc/mosquitto/mosquitto.conf.

2024-03-11T08:04:07: Opening ipv4 listen socket on port 1883.

2024-03-11T08:04:07: Opening ipv6 listen socket on port 1883.

2024-03-11T08:04:07: mosquitto version 2.0.11 running

2024-03-11T08:12:19: New connection from 192.168.1.106:42466 on port 1883.

2024-03-11T08:12:19: New client connected from 192.168.1.106:42466 as auto-765394D0-A846-9ACA-02F6-2E21DD6EF22B (p2, c1, k60, u’rei’).

2024-03-11T08:12:19: Client auto-765394D0-A846-9ACA-02F6-2E21DD6EF22B disconnected.

---

<div class="post-metadata">

**Author:** ![roger.light](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@roger.light](https://forum.cedalo.com/u/roger.light)\
**Post date:** [March 12, 2024, 9:29am UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/6 "2024-03-12T09:29:25Z")

</div>

Your ACL file contains this:

```auto
topic readwrite MQBT1
user rei

```

This produces ACLs that allow read/write access on the MQBT1 topic for clients that connect _without_ a username. It also creates a user `rei`, but then does not create any ACLs for that user.

```auto
mosquitto_sub -h 192.168.1.106 -u roger -P xyzexample’ -t MQBT1
mosquitto_pub -h 192.168.1.115 -u roger -P xyzexample’ -t MQBT1 -m “hello”

```

These two commands both connect using a username of `roger`, but there are no ACLs defined for a user `roger`, so they do not get access.

Changing your ACL file to this would work:

```auto
user roger
topic readwrite MQBT1

```

Also, check you are using the correct IP address - you are using a different one in the mosquitto\_sub and mosquitto\_pub commands.

Regards,

Roger

---

<div class="post-metadata">

**Author:** ![preWarp](https://avatars.discourse-cdn.com/v4/letter/p/ee7513/32.png) [@preWarp](https://forum.cedalo.com/u/preWarp)\
**Post date:** [March 12, 2024, 1:08pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/7 "2024-03-12T13:08:44Z")

</div>

Sir,

Thank you for pointing out those issues with my configuration.

I do have a question about host addresses for mosquitto\_sub and \_pub clients.

I have one machine that subscribes to a topic and the other publishes to the given topic.

Do I need to provide the host addresses of the machine that is subscribing and the host address of the machine that is publishing?

This is why I use two different IP addresses for the -h option when using the clients.

Is this an incorrect understanding of  
(-h) usage?

---

<div class="post-metadata">

**Author:** ![norbert](https://avatars.discourse-cdn.com/v4/letter/n/f6c823/32.png) [@norbert](https://forum.cedalo.com/u/norbert)\
**Post date:** [March 12, 2024, 4:31pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/8 "2024-03-12T16:31:46Z")

</div>

The -h (host) option specifies the hostname or IP-Address of the broker the client should connect to. In the MQTT-Protocol the MQTT-client (publisher/subscriber) actively have to connect to the MQTT broker (Mosquitto in your case). Once both clients are connected to the same broker the subscriber will be able to receive the message published by the publisher.

---

<div class="post-metadata">

**Author:** ![preWarp](https://avatars.discourse-cdn.com/v4/letter/p/ee7513/32.png) [@preWarp](https://forum.cedalo.com/u/preWarp)\
**Post date:** [March 12, 2024, 9:03pm UTC](https://forum.cedalo.com/t/mqtt-5-0-broker-is-active-messages-are-not-displaying/947/9 "2024-03-12T21:03:45Z")

</div>

This was my biggest misunderstanding and root cause. I had one message and two queues. I would give the IP address of alternate brokers for my sub/pub clients.

I also got to work with the acls after I started to see the message on its corresponding broker using only one IP address (and one broker) at a time.

Now my acls are working great. I created a second user whom I could block or allow by changing acls in my acls file.

Thanks for your help.

I will be trying rabbitMQ soon so I can use a broker with commands in the form of source code. I want to try using PHP at first.

But now that I have mosquitto I will always use it because it can be controlled with Linux shell keywords. Much more straightforward.