Reverse ptr record

[#1]

Hi all.

Currently hosting my own mail server handling email for gooduse.co.uk.

Everything else is setup correctly.

Got flagged on Spamhaus PBL list.

SMTP Banner Check Reverse DNS does not match SMTP Banner More Info
SMTP Reverse DNS Mismatch OK - 80.229.248.90 resolves to lazyd0g.plus.com
SMTP Valid Hostname OK - Reverse DNS is a valid Hostname
SMTP TLS OK - Supports TLS.
SMTP Connection Time 1.031 seconds - Good on Connection time
SMTP Open Relay OK - Not an open relay.
SMTP Transaction Time 3.391 seconds - Good on Transaction Time


https://mxtoolbox.com/SuperTool.aspx?action=mx%3agooduse.co.uk&run=toolpage# 

Pref Hostname IP Address TTL
10 lazyd0g.plus.com 80.229.248.90 24hrs
DMARC Record Published DMARC Record found
DMARC Policy Not Enabled DMARC Quarantine/Reject policy enabled
DNS Record Published DNS Record found

I requested a reverse ptr record via the "Help Assistant" and got this reply.

I'm afraid that we are unable to edit the domain record on lazyd0g.plus.com. This domain points to the Plusnet provided webspace and we do not offer any changes to this with regards to our support level.

Is this correct? www.lazyd0g.plus.com *does* resolve to plusnet webspace however, http://lazyd0g.plus.com does not.

Should I have asked for something different?

ta for your input.

Steve

[#2]

Hi @lazyd0g

We can't alter the .plus.com rDNS, but we can add a custom one based on your domain name.

If you can create a forward record i.e. something.yourdomain.co.uk, then we can set up the reverse for you from this end so that something.yourdomain.co.uk looks up to your own IP address.

Therefore, if you can create the forward record and let us know what it is via the ticket on your account, we can get this set up from this end for you.

Thanks

[#3]

OK. forget my question! Solved it.  \0/

Managed to change my smtp banner to lazyd0g.plus.com

Seems to have resolved the issue.

[#4]

@lazyd0g, the reply you received via the Help assistant was misinformed.

The crux of the issue is this:

SMTP Reverse DNS Mismatch OK - 80.229.248.90 resolves to lazyd0g.plus.com 

Which is related to the reverse DNS record for your IP address.

We can change this for you despite what you were told. Normally we would ask you to prove ownership of the domain by creating a forward A record pointing to your Plusnet IP address, but that's not necessary in your case as you already have an MX record pointing to lazyd0g.plus.com:

C:\Users\604573344>nslookup -type=mx gooduse.co.uk
Server:  UnKnown
Address:  212.159.8.120

Non-authoritative answer:
gooduse.co.uk   MX preference = 10, mail exchanger = lazyd0g.plus.com

If you decide you want to change your SMTP banner back to gooduse.co.uk, then I'll happily change the reverse DNS of your IP to match.

PS. Doesn't make much difference in the grander scheme of things, but it's arguably more professional to configure the MX records for gooduse.co.uk like this:

gooduse.co.uk.      MX       mail.gooduse.co.uk.
mail                A        80.229.248.90

[#5]

Hi Bob,
yes please! It's always nice to have things properly complete! 🙂

Thank you.

Steve

[#6]

---

@bobpullen wrote:

Normally we would ask you to prove ownership of the domain by creating a forward A record pointing to your Plusnet IP address...

@lazyd0g, looks like you're going to have to do this. There's now a validation check in place at our side that makes sure the forward record matches the reverse when trying to change an rDNS record.

Couple of options:-

1. You create an A record with the domain host to point gooduse.co.uk to 80.229.248.90. This assumes of course that gooduse.co.uk is not being used for anything else (email accepted). We then change rDNS for the IP and you update your smtp banner to gooduse.co.uk

2. If gooduse.co.uk is being used for something else, then you could configure your MX records like I suggested previously and we could change the rDNS for the IP to mail.gooduse.co.uk instead. You then update your smtp banner to mail.gooduse.co.uk

[#7]

Hi again @bobpullen

seems a bit hoop-jumpy given I obviously have control of gooduse.co.uk.

Anyways, A record created:

host -a gooduse.co.uk
Trying "gooduse.co.uk"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55141
;; flags: qr rd ra; QUERY: 1, ANSWER: 11, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;gooduse.co.uk. IN ANY

;; ANSWER SECTION:
gooduse.co.uk. 86400 IN TXT "google-site-verification=uRICq8iwkmw_VrNY2KF65PMbktMaTRQxkCova7JNuj0"
gooduse.co.uk. 86400 IN TXT "v=spf1 mx a:lazyd0g.plus.com include:spf.ukservers.net ~all"
gooduse.co.uk. 86400 IN SOA ns0.phase8.net. support.phase8.net. 2019022101 28800 3600 604800 86400
gooduse.co.uk. 86400 IN MX 10 lazyd0g.plus.com.
gooduse.co.uk. 86215 IN A 35.172.94.1
gooduse.co.uk. 86215 IN A 80.229.248.90
gooduse.co.uk. 86215 IN A 85.233.160.147
gooduse.co.uk. 86215 IN A 100.24.208.97
gooduse.co.uk. 86400 IN NS ns0.phase8.net.
gooduse.co.uk. 86400 IN NS ns1.phase8.net.
gooduse.co.uk. 86400 IN NS ns2.phase8.net.

ta.

Steve

[#8]

@lazyd0g, thanks. It'll need to wait until I'm back in the office on Monday. Give me a nudge in the afternoon if I've not responded by then.

[#9]

Hi @bobpullen

this is a nudge.......

nudge, nudge!

[#10]

Grrr, still giving me the same error:

"We cannot change the rDNS if the record doesn't resolve to the IP. Get the customer to change this and try again."

Are you able to remove the other A records? I'd imagine that will do the trick.

gooduse.co.uk.          86343   IN      A       35.172.94.1
gooduse.co.uk.          86343   IN      A       100.24.208.97
gooduse.co.uk.          86343   IN      A       85.233.160.147

Alternative is for me to enquire about one of our Ops engineers making a manual change. That's likely to be a fairly laborious process though (if it's even possible).

[#11]

Hi again @bobpullen

might take a bit longer update at your end of the internet.......  

host -a gooduse.co.uk
Trying "gooduse.co.uk"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39745
;; flags: qr rd ra; QUERY: 1, ANSWER: 8, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;gooduse.co.uk.            IN    ANY

;; ANSWER SECTION:
gooduse.co.uk.        86350    IN    TXT    "v=spf1 mx a:lazyd0g.plus.com include:spf.ukservers.net ~all"
gooduse.co.uk.        86350    IN    TXT    "google-site-verification=uRICq8iwkmw_VrNY2KF65PMbktMaTRQxkCova7JNuj0"
gooduse.co.uk.        86350    IN    MX    10 lazyd0g.plus.com.
gooduse.co.uk.        86350    IN    SOA    ns0.phase8.net. support.phase8.net. 2019022801 28800 3600 604800 86400
gooduse.co.uk.        86350    IN    A    80.229.248.90
gooduse.co.uk.        86350    IN    NS    ns1.phase8.net.
gooduse.co.uk.        86350    IN    NS    ns2.phase8.net.
gooduse.co.uk.        86350    IN    NS    ns0.phase8.net.

Received 340 bytes from 127.0.0.53#53 in 2 ms

[#12]

@lazyd0g, got there in the end

"Your reverse DNS has now been updated and the changes should take effect within 24 hours."

Let me know if you still can't see any change come tomorrow.

[#13]

Hi @bobpullen 

Thank you.

[#14]

I have the same issue as detailed in this community post https://community.plus.net/t5/Tech-Help-Software-Hardware-etc/Reverse-ptr-record/td-p/1615136

I have a fixed IP Address 212.159.45.30 and am running a mail server with 3 domains on it. The DNS for these domains I manage myself through https://www.123-reg.co.uk/

So I would like:

webmail.hermes-it.co.uk for a reverse DNS lookup to resolve to 212.159.45.30
webmail.ecalpemos.co.uk for a reverse DNS lookup to resolve to 212.159.45.30
webmail.phaedra.me.uk for a reverse DNS lookup to resolve to 212.159.45.30

If I can only have one domain resolving to 212.159.45.30 then it should be webmail.hermes-it.co.uk

If you need to speak to me about this, please phone me on either 01252 626 878 or 07833 621 612

Thanks

Trisha

[#15]

Old news, but in case anyone is looking at this - what spgrnic is asking for isn't possible.  Reverse DNS works on the IP address, and returns the PTR entry, which is the 'text' value.  So it's only possible to map an IP address to a single domain name.  You'd need separate IP addresses to support each domain.