DNS usage question

[Jay Moore]

I'm running sendmail on my 5.2.1 system, and have a number of DNSBLs set up in 
my sendmail configuration.  I am not currently running BIND (or any other 
nameserver), and therefore have configured my system to use one of my ISP's 
DNS servers.

I've noticed that each attempted connection to my mail server now generates a 
flurry of DNS requests from my mail server to my ISP's DNS server.

I'd like to streamline this process, but I don't really want to take on DNS 
administration. I've heard about caching DNS servers, and "tiny DNS", and I 
wondered if they might suit my needs.

Comments, or recommendations??

Thanks,
Jay