Reverse Dns Question...is it really necessary or not?

[Kevin Darcy]

Christophe NGO wrote:

>Hi,
>
>I have my own dns server using Bind 9.x. I have setup all the zones
>for eacb of my domains! Here my question:
>
>if no reverse dns are setup for my domains, is it possible that I may
>miss couple of emails? Some of my friends or clients have often some
>difficulties to send me emails (Mails strangely bounce)
>
I think that bears further looking into. It's _possible_ that the lack 
of reverse records is the root cause, since some misguided mail 
servers/admins use reverse lookups as a kind of litmus test for spam (as 
if spammers couldn't come up with their own reverse records, duh).

>I have an other question...does the reverse dns have to be setup on
>the ISP server or on my dns server
>
The reverse DNS tree is delegated hierarchically, so unless your ISP has 
taken special steps to delegate your chunk of the address space to your 
nameservers, the reverse records will need to be added in their DNS. 
Note that special games may have to be played if your address range is 
smaller than a /24, since reverse DNS is delegated on octet boundaries, 
and many ISPs don't want to be bothered delegating each address in the 
range as a separate zone (see RFC 2317 for details).

                                                                         
                                       - Kevin