Duplicate Local Port in Virtual Guest's /proc/net/tcp

Question

I'd like to understand the following two entries in my VirtualBox's guest's /proc/net/tcp:

   6: 00000000:18EB 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 9581 1 0000000000000000 100 0 0 10 0
  39: 6C38A8C0:18EB 0138A8C0:E3F8 01 00000000:00000000 02:000061D8 00000000     0        0 11029 2 0000000000000000 20 4 1 10 -1
  33: 6C38A8C0:18EB 0138A8C0:E3F9 01 00000000:00000000 02:000061D8 00000000     0        0 11031 2 0000000000000000 20 4 29 10 -1
  42: 0100007F:18EB 0100007F:DB7C 01 00000000:00000000 02:000062A5 00000000     0        0 13182 2 0000000000000000 20 4 29 10 -1

I see above that the same 6379 port (hex: 18EB) is duplicated, once in 127.0.0.1 twice with another local IP (192.168.56.102) which corresponds to my vboxnet0 host-only adapter (communicating to my host at 192.168.56.1), and once more as 0.0.0.0. Is this normal?

Why is this behaviour present? What would be a good situation when this behaviour is present as well, other than the above case?

Many thanks