The portmapper (rpcbind) listens to UDP and TCP on multiple interfaces. The UDP version was listening on interface 10.0.0.0.1 as I expected. What was the TCP version doing listening on all interfaces? Also, what was port 1007 UDP doing? I checked my /etc/rc.conf file to see if I had messed up the synatx. I finally looked at the man page and clarified the -h switch. Now my only alternative is to firewall the interfaces where I do not want rpcbind to listen.”]
Source: https://taosecurity.blogspot.com/2005/07/unable-to-specify-interface-for-tcp.html