Bind open to query from anyone

[Chris Henderson]

I've setup a secondary name server which works as a secondary or slave
name server for my zone or domain name. However, I have tested and
noticed that I can query for non-authoritative answers from my
secondary or slave name server from outside my network. That is, any
one can use my name server to query any host name, eg. www.google.com,
www.yahoo.com etc. Is this a bad idea? How can I stop this?

Thanks for any suggestions.