AS/400 DNS server?

Hi,
I have lots of questions about running a DNS server on my AS/400.  I'm
currently running a few web sites on my 170, and it's working well
(thanks in large part to the contributors to this list).  I'm not
running the SMTP server, I'm hosting my "main" web site on Concentric
servers and letting them deal with my email needs.  I have not yet
figured out how to run smtp servers for multiple domains' , ie., I'd
need to run email for each of the websites on my AS/400.  I've only seen
examples of running one and I'm not sure how to run multiple, or even if
it's possible with the directory structure built in to the operating
system.  And, I'd probably lose the niceties of letting one of the "big
boys" handle my email, like copy, forward, etc. at the server level.
Plus, I'm not sure I want to open myself up for the traffic that email
could bring.
About DNS:
I don't have a good understanding of DNS, the examples I've seen seem to
apply to an intranet environment.  And I've seen disturbing statements
about directory entries being set up for everyone who sends me email,
including the tons of spam that I receive daily.  I really don't want my
directory to contain hundreds (or thousands) of entries.  I like things
as "clean" as possible.
1. If I start up a DNS server, am I opening myself up to "passsing thru"
traffic from the whole world?  In other words, are we talking about a
world-wide DNS server, which will be "propagated" with every dns entry
in the known universe?
2. Does running DNS on my AS/400 eliminate the need to have DNS entries
for my website(s) located on my ISP's server?  In other words, will I be
the "master of my own fate", eliminating aggravations when other DNS
servers go down (as occasionally happens to me, this afternoon, for
example)?  If my web server goes down, my dns server may as well be
down, since no one will be able to get to my website anyway.

I hope that, as usual, I'm overcomplicating this.  I'm sure it will be
easy to set up, but I'm not sure about the ramifications of doing this.

Any help or clarification will be appreciated......

--
William A.(Tony) Corbett
corbett@asresources.com
http://www.asresources.com
http://www.cbt400.com


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