Question

. the www.ietf.org contains several images. before retrieving each image, does your host issue a new dns query? why or why not?

Answer 1

No, the DNS entries are cached locally.

Step-by-step explanation:

Your computer has a local store to remember DNS-to-IP mappings. You can even view it by typing:

ipconfig /displaydns

And you can clear it by typing:

ipconfig /flushdns

This doesn't hurt because from that point on, your computer will do new DNS queries and rebuild that cache.