Re: AS/400 DNS server?

-----Original Message-----
From: William A.(Tony) Corbett <corbett@asresources.com>
To: midrange-l@midrange.com <midrange-l@midrange.com>
Date: Friday, June 23, 2000 11:59 PM
Subject: AS/400 DNS server?


>About DNS:
>I don't have a good understanding of DNS, the examples I've seen seem to
>apply to an intranet environment.

Yes.  A DNS is only responsible for *it's* domain, not someone else's.  You
set up a DNS to address YOUR machines, not someone else's.  This has the
appearance of intranet because it applies internally, but exposes those
machines to internet access.

>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.

This is the auto registration and applies to e-mail.  It is optional and
does not need to be turned on, however, before the 400 can send mail, you
need the addressing.  Note that if you use some other mailer (Netscape,
Outlook, Eudora, etc.) and use the 400 as a POP3 server, then the address
book is usually contained in the mailer software and you can choose to use
that.  Also note that sending from the mailer does not have to go through
the 400.

>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?

No. Again, you maintain your own addresses.  For anything unresolved, the
address is sent to your ISP for resolution through there DNS. The
"propagation" that you speak of would be sending your entries (only) to
another internal DNS (backup) server. This is a zone transfer, but no, you
don't maintain a universe full of entries.  That was the old hosts file
method.  DNS is distributed.

>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.
>

Depends.  The ISP will still have your DNS listed in there DNS as the server
with authority over your domain name(s).  They will still have to maintain
these entries, but you will now maintain your own internal set.  As for the
down time, if the ISP's DNS goes down, you are essentially disconnected.
Having your own DNS does not fix this.  Also note that if YOUR DNS goes
down, the ISP can't really do anything to help you.  They can point the
traffic to you, but you can't get it to the proper machine.  For business
and critical applications, two DNS servers, a primary and a secondary, are
essential.

As for setting it up, yes, it is fairly easy throught the 400.  The 400 can
make the reverse entries automatically for you.  This is a source of errors
in setting up a DNS on say, Linux.  BUT... before you begin, you need to
understand the DNS scheme.  Setting up a DNS incorrectly on the internet can
wreak considerable havoc to internet traffic and your ISP may cut you off
until you fix it.

===========================================================
R. Bruce Hoffman, Jr.
 -- IBM Certified AS/400 Professional System Administrator
 -- IBM Certified AS/400 Professional Network Administrator
 -- IBM Certified Specialist - AS/400 Administrator
 -- IBM Certified Specialist - RPG IV Developer

"If all you have is RPG, then everything looks like a 400!"



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