DNS Security

[wwebb at adni.net]

On a server that acts as a master for CAP.GOV, the named.conf 
has the following as part of options,

	allow-recursion { 198.88.0.19; 198.88.0.39; };
      fetch-glue no;

As an aside, I don't believe "allow-recursion" is discussed in the 
DNS & BIND book (3rd Edition) but I learned about it in ISC 
documentation.  Beginning in what version of Bind is "allow-
recursion" allowed? 

At any rate,  the server  seems to be working well, acting 
authoritatively for its zones, (using much less memory than when it 
was recursive),  however, entries such as the following show-up 
occassionally in the message log:

unapproved recursive query from [192.31.106.5].53 for njwg.cap.gov

What is the significance of such entries?

Thanks...