Group Replication System Variables A value of  DEFAULT , which is the default setting, means joining members use the existing member’s standard SQL client connection, as specified by MySQL Server’s  hostname  and  port  system variables. If an alternative port number is specified by the  report_port  system variable, that one is used instead. The Performance Schema table  replication_group_members  shows this connection’s address and port number in the  MEMBER_HOST  and  MEMBER_PORT  fields. This is the behavior of group members at releases up to and including MySQL 8.0.20. Instead of  DEFAULT , you can specify one or more distributed recovery endpoints, which the existing member advertises to joining members for them to use. Offering distributed recovery endpoints lets administrators control distributed recovery traffic separately from regular MySQL client connections to the group members. Joining members try each of the endpoints in turn in the order they are specified on the list. Specify the distributed recovery endpoints as a comma-separated list of IP addresses and port numbers, for example: IPv4 and IPv6 addresses and host names can be used in any combination. IPv6 addresses must be specified in square brackets. Host names must resolve to a local IP address. Wildcard address formats cannot be used, and you cannot specify an empty list. Note that the standard SQL client connection is not automatically included on a list of distributed recovery endpoints. If you want to use it as an endpoint, you must include it explicitly on the list. For details of how to select IP addresses and ports as distributed recovery endpoints, and how joining members use them, see Selecting addresses for distributed recovery endpoints. A summary of the requirements is as follows: 3796 Command-Line Format --group-replication-allow-local- lower-version-join[={OFF|ON}] System Variable Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Boolean • group_replication_allow_local_lower_version_join •The SSL requirements for the connection are as specified by the group_replication_recovery_ssl_*  options. •The IP addresses do not need to be added to the Group Replication allowlist specified by the group_replication_ip_allowlist  or  group_replication_ip_whitelist  system variable. •Appropriate permissions are required for the replication user for distributed recovery if the admin_port  is used. •The ports do have to be configured for MySQL Server using the  port ,  report_port , or admin_port  system variable. •The IP addresses do not have to be configured for MySQL Server, but they do have to be assigned to the server. group_replication_advertise_recovery_endpoints= "127.0.0.1:3306,127.0.0.1:4567,[::1]:3306,localhost:3306"