PTR record question.

Re: PTR record question.

From:

Date:

Time:

There are a few misconceptions here, mostly relating to definitions of terms.

At 8:16 PM -0500 3/19/2000, andrew wrote:
>hmmm..well, QDNS Pro is trying to set up the reverses automatically, but if
>you're not authoritative for the domain, you should delete them.

Correct. Except the reverse zone is not, technically, a "domain". It's a zone, but not a domain. (Every domain is a zone, but not vice versa.)

>However, it sounds like you *are* authoritative for the domain (s), so yes,
>you would need to set up the reverse. It doesn't matter whether the ISP is
>giving you a class C or one IP...if you're the primary DNS for that domain,
>you need to provide the reverse.
>
>DNS relates to domains...domains encompass ranges of IPs...so if the
>upstream is providing you with the IPs, and they're not part of their
>domain, then they're your responsibility.

DNS relates to zones. Most zones are domains, but reverse zones are not. Domains do not encompass ranges of IP addresses, reverse zones do.

Being authoritative for a domain does not automatically make you authoritative for the reverse zone for the IP addresses you use. It is common for an ISP to try to keep control of the reverse zone if they're not routing an entire class C subnet to you, mostly because they don't understand how much easier their lives can be if they delegate your subnet to you.

However, if your ISP decides not to delegate, it's perfectly workable for them to handle the reverse data for your IP addresses. In this case, though you have use of the addresses, and though your domain zones reference those IP addresses, you don't maintain the reverse zone records. If someone wants to look up the reverse record for the address used by your mail server, they'll query your ISP's DNS servers.

>IOW, you will need a PTR for you Primary DNS, since it's within the IP range
>you're responsible for. And you'll need a PTR for your mailserver (s), or
>other servers doing reverses to authenticate mail coming from your domain
>will bounce it.

This is only true if the reverse zone is delegated to you.
____________________________________________________________________
Chris Buxton cbuxton@menandmice.com
Men & Mice http://www.menandmice.com
Makers of: QuickDNS Pro

Sales:
888/4-DPOINT

Support:
858/452-3696