Re: Reverse DNS

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Hi Gureey,

The forward - reverse DNS match can be done with your ISP's domain, or with
your domain. Either way will work. Remember that although it is possible
to have the same IP address associated with many A records, only one PTR
record will display for an IP address. What your ISP is doing is allowing
you to use that one PTR record to show your domain instead of theirs.

What this does (among other things) is that when someone does a traceroute
to your network, they will see your domain instead of the domain of your
ISP. Also, there is a choice of only setting up reverse DNS on the IP
address of your mail server, or setting it up for all your IP addresses. It
is generally a good idea to set it up for all IP addresses, but as Herb
said, it isn't absolutely necessary.

--
Greg Lindsay [MSFT]

Disclaimer: This posting is provided "AS IS" with no warranties, and confers
no rights.

"Herb Martin" <news@xxxxxxxxxxxxxx> wrote in message
news:OjIb1l2LHHA.4000@xxxxxxxxxxxxxxxxxxxxxxx

"Gureey" <Gureey@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:0BEF2DC2-2231-4893-B703-488673566AE8@xxxxxxxxxxxxxxxx
Thanks Grey and Herb,

I understand you point. But with our previous ISP, i didnt made any entry
in
our DNS. My previous ISP only create a record in their domain as you
describe, pointing toward our IP address .

You don't actually HAVE to do that -- but generally it is a good
idea.

Some (many/most) receiving SMTP servers will test for that PTR
record, some (not as many) will test for a match back to an A
record in your PUBLIC DNS. Most which do this expect the
name to match the HELO name of the SMTP server no matter
WHAT you call your SMTP server internally or for which
zones/domains it sends email.


Any ways thanks for you response..

"Greg Lindsay [MSFT]" wrote:

I agree with Herb, this is an ISP that is taking the trouble to give
you
more than just generic reverse DNS entries in a domain that they own.
That's kind of rare.

The extra entries they are sending to you is just so you can complete
the
loop (PTR = A record = IP address). If they were using one of their
domains
for the reverse entries, they would add these themself, but since they
are
using your domain, they are giving you the information. The "loop" I
mentioned is required by some email servers. If you don't have
matching
forward and reverse DNS, they will reject your emails.

--
Greg Lindsay [MSFT]

Disclaimer: This posting is provided "AS IS" with no warranties, and
confers
no rights.

"Herb Martin" <news@xxxxxxxxxxxxxx> wrote in message
news:OzSaZ3tLHHA.5000@xxxxxxxxxxxxxxxxxxxxxxx

"Gureey" <Gureey@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:C18A8BEB-FB8A-43D8-9FBA-3337DE8840DE@xxxxxxxxxxxxxxxx
Hello Friends,

I asked my ISP to setup a reverse DNS for our IP address. I get a
response
to setup a fwd in my zone file and then my ISP add reverse. He also
send
me a
list of name with corresponding IP address to add in my forwad zone
like

gw IN A 198.168.0.49
hostXX IN A 123.34.345.22

then they add following in their reverse zone.

49 IN PTR gw.xxxxxxx.com
hostxx IN PTR hostxx.xxxxx.com

Is this is the way to created REV DNS.

Yes (it sounds like) the ISP is being kind (not all are) and
allowing YOU to pick the names -- many ISPs just give you
a generic record name in the PTR and you have to figure out
how to deal with it to make it convenient (CNAME etc.).

I think they only have to create PRT
record in their DNS reverse zone pointing towards our IP.

Correct but that is what you said above:
> then they add following in their reverse zone.
> 49 IN PTR gw.xxxxxxx.com
> hostxx IN PTR hostxx.xxxxx.com

Please tell how can I setup this, Coz we are facing problems to
sending
mail
from our server.

You will also need to give your EMAIL server the same
"HELO" or SMTP Server name in the Email configuration.
This is specific to the particular SMTP server software and
the name for this setting may vary but it is the "official" name
of the SMTP server when it SENDS email, i.e., the one it
reports when it says "HELO" to other SMTP servers.

Any help is appreciated
Regards
G.









.

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