How would one check to see if ipv4 --> ipv6 translations is happening?

netstat gives me the following:
tcp6 0 0 :::5544 :::* LISTEN

However, only the following in tcp (vs tcp6):
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN

!sysadmin