new public ip causing mail delivery problems

we have a domain name hosted by 1and1. we have an mx record that points to our exchange mail server public ip address.

we have just replaced our internet service provider and have been issued with a new public up address. all of our dns records have been updated to reflect the ip change.

all seems to work ok, but we are getting a few messages bouncing back to us.

on checking further using mx toolbox we are advised that we do not have a reverse lookup ptr registered.

on contacting 1and1 they tell me that they cannot add a ptr record to our dns.

am i right in thinking this could be the cause of our problem, and if so, how would we resolve it if 1and1 can’t provide what i consider to be a basic requirement.

one other thought was that recipients would have to update their white lists as mail currently being issued has a different ip associated with our domain name.

any advice / suggestions would be much appreciated.

many thanks
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Kapila JayasingheCommented:
My advice is not to use PTR. SPF record is the preferred method. Add SPF record in your DNS provider


v=spf1 mx -all

Open in new window

MXToolBox has a SPF record generator
Dr. KlahnPrincipal Software EngineerCommented:
The first question I'd ask is this:  Specifically, why are those messages being bounced back?  What's the reason text provided by the remote MTA following the 5xx permanent error code?

MX Toolbox may be right that your domain does not have RDNS, and perhaps that is the source of the problem ... but perhaps not.  Over 12 years while siting my own MTA and using dynamic DNS I saw perhaps 5 messages bounce for lack of RDNS.  Find out the real reason why first.

Sounds typical of 1&1.  They're helpless.  I registered one domain name through them a couple years back and after one week of their service I was eagerly waiting to transfer it out.
AmitIT ArchitectCommented:
I did similar change for my client, where IP address were changed. In that change, i created new A record and New PTR record, update SPF record with new IP's. Update, public facing firewall with new IP's. In your, case your ISP or whoever managing DNS, need to update or create PTR and SPF with new IP's. Else you domain will be blacklisted.
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nigelbeatsonAuthor Commented:
ok thanks for your comments. i will give them some thought and provide additional information regarding the ndr.

we have our internet service provider who provided our static ip, 1and1 host our domain name and provides our dns, and our website is hosted by somone else.

1and1 tell me they cannot issue a reverse dns ptr for some inexplicable reason! i have not worked  spf before, so will have to look into that.

many thanks
AmitIT ArchitectCommented:
Ya, some ISP says that, in my case also, we had similar issue. What i did? I changed to ISP, who can do it.
SPF is not a replacement for a reverse (PTR) record as such - you should have both, but regardless, you definitely should setup SPF.

If your ISP won't provide it, then that implies that they are not really a 'business focused' ISP, more aimed as residential customers.

I would suggest moving to an ISP that can setup reverse DNS lookup for you - it will make it more likely that your email will get through.

WadskiIT DirectorCommented:
Whilst everyone is talking about PTR and SPF records I think the advice you need simply to contact your ISP to add the ptr record.

1and1 is your domain host and that would affect inbound traffic (spf record)
ISP is your internet provider and that would affect outbound traffic.  (ptr record)

It's your outbound traffic you have a problem with as there is no reverse lookup on your IP address to your mailserver

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nigelbeatsonAuthor Commented:
many thanks

1and1 host our domain name and public dns.

we have a separate service provider for our internet services, who provide our public ip.

are you saying that it is our isp that needs to add a reverse lookup, as you are correct it is outbound mail that we are having trouble with.

many thanks
nigelbeatsonAuthor Commented:
looking at the ndr of the bounces mail, they mainly indicate that there is no reverse dns ie no RDNS for this entry

many thanks
Jeff GloverSr. Systems AdministratorCommented:
1 and 1 does not host the reverse lookup zone for your IP address. That is owned by the ISP and maintained by them. I would suggest you try contacting your new ISP. Many have a procedure in place for requesting a PTR record. And I also echo what Kapila said. Use SPF records. (I would do both if possible)
nigelbeatsonAuthor Commented:
many thanks to all. i havenpw requested a ptr from our isp. i’m hopeful this matter will be resolved shortly.😊👍
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