By default, Docker swarm services will listen on all interfaces on the host. This may not be necessary for the operation of the swarm where the host has multiple network interfaces. Rationale: When a swarm is initialized the default value for the --listen-addr flag is 0.0.0.0:2377 which means that swarm services will listen on all interfaces on the host. If a host has multiple network interfaces this may be undesirable as it could expose swarm services to networks which are not involved with the operation of the swarm. By passing a specific IP address to the --listen-addr, a specific network interface can be specified, limiting this exposure. Impact: None
Solution
Resolving this issues requires re-initialization of the swarm, specifying a specific interface for the --listen-addr parameter. Default Value: By default, Docker swarm services listen on all available host interfaces.