Problems with BIND named

[Doug Hardie]

FreeBSD 4.6.  I am encountering problems with named.  It is starting 
again after several years of no problems to eat up all my swap space 
and then exit.  So I added a datasize 30M to named.conf and now the 
data size sits at about 30 MB.  However, after about 12 hours of 
working fine, I got the message cannot allocat memory and it exited 
again.  This is a mail server that handles a high volume of traffic and 
looks up a large number of names.  Perhaps limiting the datasize is not 
the right approach, but I need to make it remove entries from its 
tables rather than keep them for days.  What is the best approach for 
this?