forwarders

[Amira Othman]

Hi all

I configured bind9 on centos 5.8 server that has postfix mail server running
on. When I added my ISP DNS ips to forwarders the mail server stopped
sending mails and gives me DNS error

requires that all mail servers must have a PTR record with a valid Reverse
DNS entry. Currently your mail server does not fill that requirement.

But I didn't change mail server configuration and its MX record points to
one of ISP DNS as I am still using their DNS. What's wrong on my
configuration or what's missing?

I also can't nslookup my DNS server although I added reverse zone in my
zones. Should I have PTR in registrar also or it's just in my DNS server?

Regards

[Čiernik Tomáš]

Hello,

Not registrar, but ISP.

>
> Regards
>
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[Barry Margolin]

In article <mailman.886.1338202...@lists.isc.org>,

"Amira Othman" <a.ot...@cairosource.com> wrote:

> Hi all
>
> I configured bind9 on centos 5.8 server that has postfix mail server running
> on. When I added my ISP DNS ips to forwarders the mail server stopped
> sending mails and gives me DNS error'
>
> requires that all mail servers must have a PTR record with a valid Reverse
> DNS entry. Currently your mail server does not fill that requirement.

I don't believe that changing your forwarders could have caused this.
This is the receiving server trying to do a reverse lookup of your IP,
which should involve your authoritative DNS, but forwarders only affects
caching DNS.

> But I didn't change mail server configuration and its MX record points to
> one of ISP DNS as I am still using their DNS. What's wrong on my
> configuration or what's missing?

This has nothing to do with MX records, which are used for your incoming
mail. The error is happening on outgoing mail, which uses your reverse
DNS.

>
> I also can't nslookup my DNS server although I added reverse zone in my
> zones. Should I have PTR in registrar also or it's just in my DNS server?

Your ISP needs to delegate the reverse DNS to your servers. This should
have been necessary all along.

--
Barry Margolin
Arlington, MA

[Lyle Giese]

On 05/28/12 05:49, Amira Othman wrote:
> Hi all
>
> I configured bind9 on centos 5.8 server that has postfix mail server running
> on. When I added my ISP DNS ips to forwarders the mail server stopped
> sending mails and gives me DNS error
>
> requires that all mail servers must have a PTR record with a valid Reverse
> DNS entry. Currently your mail server does not fill that requirement.
>

> But I didn't change mail server configuration and its MX record points to
> one of ISP DNS as I am still using their DNS. What's wrong on my
> configuration or what's missing?
>

> I also can't nslookup my DNS server although I added reverse zone in my
> zones. Should I have PTR in registrar also or it's just in my DNS server?
>

> Regards
>
> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list
>
> bind-users mailing list
> bind-...@lists.isc.org
> https://lists.isc.org/mailman/listinfo/bind-users

Amira,
I am assuming you are talking about cairosource.com.

Your forwarders have nothing to do with your issues. It looks like you
are sending email from ip address 184.107.204.250. This has no reverse
lookup. Iweb-hosting.com is the authority for this reverse lookup as
the ip address is delegated to them. If this is the only ip addres
assigned to you, ask iweb-hosting to add a proper reverse lookup for
this ip address.

Further your MX record for cairosource.com has a TTL of 300 seconds and
the A record also has a TTL of 300 seconds for msrv.cairosource.com.
This low TTL makes it look like you have a dynamic ip address. Most
RBL's require a minimium of 12 hrs and recommend 24 hour TTL on these
two records.

Lyle Giese
LCR Computer Services, Inc.