This question already has an answer here:
Tanenbaum's Computer Networks says
The IP address 0.0.0.0, the lowest address, is used by hosts when they are being booted. It means ‘‘this network’’ or ‘‘this host.’’
[::] is IPv6 version of IPv4's
1) When does
0.0.0.0 mean this network and when this host?
2) When it means this host, does it mean all the network interfaces on this host, or just one specified network interface on this host?
3) Why does
[::] allow me to access the mysql server from other hosts in the same LAN? Does it mean this network or this host here? Why is
[::] used by mysql server, although the host is not in the case "when they are being booted"?
$ sudo netstat -ap | grep mysql tcp6 0 0 [::]:mysql [::]:* LISTEN 23683/mysqld tcp6 0 0 [::]:33060 [::]:* LISTEN 23683/mysqld unix 2 [ ACC ] STREAM LISTENING 1169294 23683/mysqld /var/run/mysqld/mysqld.sock unix 2 [ ACC ] STREAM LISTENING 1169513 23683/mysqld /var/run/mysqld/mysqlx.sock unix 2 [ ] DGRAM 1169211 23683/mysqld