RE: Reverse DNS - where is it?

Jeff,

As you know, DNS's job is to map a human-friendly name -- say
mail.dilgardfoods.com -- to a computer-friendly name -- 66.15.42.200 in
this case. It does this by asking your DNS servers for an 'A' record.

Reverse DNS does the exact opposite. It maps 66.15.42.200 to a
human-friendly name. To do this it reverses the IP and prepends it to
IN-ADDR.ARPA and then looks up a PTR record for that "host."

So, if we lookup a PTR record for 200.42.15.66.in-addr.arpa we find an
answer of 
"bdsl.66.15.42.200.gte.net" and while that's not mail.dilgardfoods.com
it is a valid domain and as such shouldn't cause any problems. 

Have you tried telnetting to your cell-phone's SMTP server and sending
the SMTP commands. You may get some error message that points you in the
right direction.

>I _can_ send email from within the office if I use web email such as my
>yahoo or verizon email address.

Actually, you're browsing the web from within the office, but you're
sending e-mail from yahoo's or verizon's servers, so you're not in the
office.

-Walden

------------
Walden H Leverich III
President & CEO
Tech Software
(516) 627-3800 x11
WaldenL@xxxxxxxxxxxxxxx
http://www.TechSoftInc.com 

Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)
 
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jeff Crosby
Sent: Tuesday, June 22, 2004 10:54 AM
To: 'Midrange Systems Technical Discussion'
Subject: Reverse DNS - where is it?

If this is the wrong forum for this question, please let me know.

Some time back I asked a question regarding why I couldn't send email to
my
cell phone (Centennial) from within our office, but could send it from
home.
Never figured it out.

The Centennial rep just yesterday said it could be that we don't have
reverse DNS set up.  I don't know DNS very well but have been in this
business long enough to know that I could royally screw things up by not
knowing what I am doing.

1) We have Verizon DSL.  CFGTCP says the DNS servers are 4.2.2.1 and
4.2.2.2.  The domain is registered at register.com.  At register.com, it
says the DNS servers are dns41.register.com and dns42.register.com.  Is
this
a problem?  Do I need to contact one of these places for reverse DNS to
be
set up?

2) I _can_ send email from within the office if I use web email such as
my
yahoo or verizon email address.  But I _cannot_ send email from Outlook
to
my cell phone.

3) Ops Nav in DNS area has 'reverse mapping' checked.  There is a
"dilgardfoods.com" listed under primary domains, but there is no
"mail.dilgardfoods.com" listed under primary domains.  Is this a
problem?

4) The iseries is behind a firewall.

Thanks.

-- 
Jeff Crosby
Dilgard Frozen Foods, Inc.
P.O. Box 13369
Ft. Wayne, IN 46868-3369
260-422-7531

The opinions expressed are my own and not necessarily the opinion of my
company.  Unless I say so.



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