Is it right Docker Swarm 1.12 using tcp6?

Hi, all.

When I created Docker Swarm, the daemon port is listening on tcp6.
Is it intended?

I wanted to listen on tcp.
Bacause I thought my swarm cluster is not work properly.

For example, when I ran a service globally and I tried to connect to the service but, only connected only one node.

And sometimes the service not create well. Stuck in ‘Assigned’ status.

4eu4yxt4auoxmr69slp97yrz9  GSSC      192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
6vttsy760v2h4psxku0d9gtq9   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
0f72yitqjvgv47n6wq3gwvig8   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
1s8iwjyag10oe0cbz5yrbdmqq   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
dfgk80k0j7m0ckgbisy0zncbu   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
ckc0ff0s43szihjgym7pc0zp3   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
0e10pxquhz6sfj6fuzk5ou35u   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
2jtcti675yozdbzwo1sputy6i   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
05fg2qxwz74xtotuu6ok2vek9   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago  
73kcoqzpiqxefof97q0ty9wb6   \_ GSSC  192.168.0.10:5000/global-service:1.4  ####  Running        Assigned 19 seconds ago

At the time, I ran the command that was ‘sudo service docker restart’ Finally, it works.
Idk why.
Im almost gonna crazy.
help me plz.
thx.

Here are my listening ports.

tcp        0      0 0.0.0.0:2000            0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0      0 192.168.0.10:2375       0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:6379          0.0.0.0:*               LISTEN     
tcp6       0      0 :::2000                 :::*                    LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
tcp6       0      0 :::2377                 :::*                    LISTEN     
tcp6       0      0 :::7946                 :::*                    LISTEN