reverse dns ISP

[ndunaz]

We will be moving from a single persistent IP to a block of 5 static IP's from our ISP. A Cisco UBR will assign the "subnet" and we will be putting in a router behind it for a dmz. On the dmz I plan to have an OS X xserve (using one static IP) that will be a web server and our external dns. Behind another router (using a second static ip as the gateway) providing NAT internal network with port forwarding for Mail and VPN, internal dns...

We have domain names "parked" at Godaddy.

When I asked our ISP about DNS, and mx records ... their reply was "We will provide forward lookup, but NO CUSTOM DNS reverse entries". Before I ask them to clarify does this mean that I can't host my own dns and/mail server because the reverse dns will not be authorative? They told me the ns servers were ns1.ispname.com and ns2.ispname.com. Or with forwarders I can have DNS find what it needs in the combination of my internal and external dns servers? Am I making any sense at all?!?!

Thank you in advance.

 

[ChrisAC]

I find it strange that the ISP won't provide custom reverse DNS. The obvious solution would be to move your DNS to a provider that will provide customer PTR records for your IP range.

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[FaiTHLeSS]

They say they wont do custom RDNS, makes me think they will have their own default RDNS for the IP which is ok, might not be what you want but it better than not having it at all. This does not stop you from hosting your own servers though. Only problem you might run into if your running a mail server some mail servers are setup to reject mail with no PTR record.

 

[ndunaz]

Thank you both for your replies. I will ask the ISP what their "default" is, I guess they don't use RFC2317 at this level of service anyway... I do want to host a mail server so maybe I have to look at dns hosting sites? Can I do that without having to switch ISP? If they are authoritative for the addresses how does this relate to the dns hosting service? Maybe I need to do more reading before I ask the ISP more about it. Anyone got any suggestions?

 

[pdurkee]

I recently ran into a similiar Reverse DNS issue. I had a mail server that kept rejecting our emails. I checked with my vendor and did not have a RDNS entry. I am using ITC Deltacom as my provider and my Domain stuff is hosted at Earthlink. At my request the telecom vendor added the RDNS and it took care of my problem. You may just need to switch ISP/telecom provider.
You can test all your settings at the link below.

http://www.dnsstuff.com/

 

[supercoups]

I am having a similiar problem with one of our clients. Our mail is being rejected with the following error:

rDNS "[x.x.x.x]" non-existent

Where x.x.x.x is our public IP address of our mail server. Do I need to have our DNS host make an entry for this IP address or do I need the ISP that owns the IP range make an entry to allow for the reverse lookup?

Thanks in advance,
Jim

 

[FaiTHLeSS]

If you havent been given reverse DNS control then you will have to request the ISP to set the rDNS for the IP.

 

[supercoups]

Do I need to request this RDNS control from the ISp that pwns the IP range?

 

[pdurkee]

Yes you need to request the RDNS from the person who gave you the IP range. In my case I got my ip address from ITC, the telcom company that supplies my T1 line. My email hosting is done internally and my web hosting for our web page is done at Earthlink. In my case I would not use Earthlink but use ITC.

pdurkee

 

[FaiTHLeSS]

Depending on what type of connection you, if you only have a single IP from your ISP then they will most likely set the rDNS for you on request. If you have a range of IP's then you might be able to get rDNS control over them.