Reverse DNS entry Mail Server

My YunoHost server

Hardware: Raspberry Pi 4 at home
YunoHost version: 4.3.6.3
I have access to my server : Through SSH | through the webadmin |
Are you in a special context or did you perform some particular tweaking on your YunoHost instance ? : no /

Description of my issue

I would like to use the full younohost project scope including the mail server.
Consequently I changed my ISP (Vodafone Germany) contract to a business one with fixed ipv4 and ipv6.
Now vodafone requires for validation purposes to place a txt-record on a subdomain.
As I am new to self hosting I have no idea where to place that record on my younohost.
The German forum gives a solution here.:

In the internal area Vodafone gives me the following guidance:
" Für Deine IPv4 Adresse kannst Du hier einen Hostnamen eintragen.
Bitte gib einen Full Qualified Domain Name (FQDN) für Deinen Host ein. Der FQDN ist eine Kombination aus Gerätenamen und Deinem Domainnamen.
Der Gerätename und der Domainname werden mit “.” verbunden zum Beispiel: “meinhost.meinedomain.de”.
Wenn Du dieses Feld leer lässt, wird ein evtl. vorhandener Eintrag gelöscht!
Du musst Dich als Inhaber Deiner Domain authentifizieren, wenn Du den DNS Eintrag einrichten oder ändern möchtest. Bitte erstell dazu mit dem folgenden TXT Record String ein TXT Resource Record. Mit dem Speichern wird die Prüfung angestoßen. Diese kann mehrere Tage benötigen."
Google Translate this into English:
“You can enter a host name for your IPv4 address here.
Please enter a Full Qualified Domain Name (FQDN) for your host. The FQDN is a combination of the device name and your domain name.
The device name and domain name are prefixed with “.” connected for example: “meinhost.meindomain.de”.
If you leave this field empty, any existing entry will be deleted!
You must authenticate yourself as the owner of your domain if you want to set up or change the DNS record. Please create a TXT Resource Record with the following TXT Record String. The check is triggered when you save. This can take several days.”

I Have the TXT Record available.

Diagnosis Output
https://paste.yunohost.org/raw/doniloyago

Looking for your great support! Thanks in advance.

You add the txt record in your registrar administration, just like you did for the A record

Hey thanks for your quick reply.
How do I get to the registrar administration?
How can I place there the txt record for IPv6 and ipv4 there?

Consciously, I did nothing with a an A record. → I am using the standard younohost domain

What do you mean with the ‘standard Yunohost domain’ ?

Did you chose one from the noho.st (etc) domains, or do you have your own .de domain?

1 Like

I don’t think that you can do it with the domains provided by yunohost.
You may have to register for a new domain name and use it to be able to add txt records.
Depends on where you live and what registrar providers you have. There is a list of providers that yunohost can handle directly.
Personally, I’m using two domains and a subdomain from a local domain provider and since I have a dynamic ip, I used freedns from namecheap to update it. Reverse dns requires a fixed ip, so I couldn’t configure it.

yes currently I am using a XXX.nohost.me and I have no own domain

Hi i have changed my ISP conract to fixed ip so should be able to configure a mail Server with my available infrastructure.

I’m not sure if I follow. If you want to host your own mail, that mail needs an address like rudi@rudihost.de or whatever your email is. You feed to register that domain and point its dns settings to your ip. In the same place where you can do this you will be able to add a txt record.

Also, when you add this domain to yunohost it will start telling you what you need to correct in those records. Be ready to open ports from your modem and once everything is working start requests to be removed from spam lists. Because your ip might be on them by default.

i am using the domain from younohost XXX.nohost.me so my mailadress looks like rudi@XXX.nohost.me.
I can remove myself from spam lists everything ok.
My Question ist how to add a txt record to the younohost domain.

I’d don’t know if that is possible. But I also don’t understand why Vodafone wants to verify your domain if you already have your own ip and your own server. So maybe ask someone else.

I would, because it is more convenient and pleasing to eye, get a personal domain name.

If I remember correct, my ISP added the reverse DNS because they owned my IP-address.

To solve all this problems with mail servers blacklist etc. I have used a VPS to host my IP via a VPN. This has been really solid for almost a year now.
See - Homemade WireGuard VPN on a VPS server

If i understand vodafone wants to check you own the domain on which you want to add the reverse DNS before to configure this reverse DNS.
So they ask you to add a txt record to give a proof that you own this domain.

In general, people doesn’t have to do this process in order to add a reverse DNS. I think other ISP/Server providers simply do a dig A DOMAIN to check the validity of the request. Vodafone seems to have a new/other process.

The problem is noho.st, nost.me and ynh.fr are free domain and we restrict which entry could be added (to avoid different kind of abuse).

You can find here the list of record that can be sent by your server: dynette/dynette.cron.py at master · YunoHost/dynette · GitHub

It’s the default DNS configuration provided by a yunohost instance.

TXT records are authorized on XXX.nohost.me , so in this case you could succeed to send this DNS configuration. You won’t be able to do it if the TXT record should be added on a subsubdomain like YYY.XXX.nohost.me

If you are in the first case, in order to send your record, you should do like this:

  1. create a file /etc/yunohost/hooks.d/custom_dns_rules/01-vodafone
  2. edit it and copy this script
#!/bin/bash
echo "[{'type': 'TXT', 'name': '.', 'value': 'THE VALUE ASK BY VODAFONE', 'ttl': 3600}]"
  1. You should try to update your dns conf:
yunohost dyndns update
  1. After 5 minutes, check if the TXT record has been correctly added:
dig TXT XXX.nohost.me @9.9.9.9
2 Likes

Yes you understood me correctly, Vodafone wants to check if I “own” the domain.

So just to doublecheck that I understood your reply correctly:
i am able to add a txt record on the XXX.nohost.me but not on a subdomain YY.XXX.nohost.me right?
→ Proceed with the three steps you described (as I am pretty fresh with Linux I will need here additional support e.g. I do not know how to create and edit a file) to add the txt record to XXX.nohst.me and cross my fingers that Vodafone accepts it.
→ If that does not work I have to buy a domain with full access on the DNS config right?

To create the hook dir:

mkdir -p /etc/yunohost/hooks.d/custom_dns_rules/

To create/edit a file:

nano  /etc/yunohost/hooks.d/custom_dns_rules/01-vodafone

Adapt my small script with the good value ask by vodafone.

Yes indeed.
You can also try to find a free domain like netlib.re (you have full control on netlib.re DNS zone). However keep in ming that netlib.re is owned and managed by a unique person.

2 Likes

Here are my results:
I guess it did not work :frowning:
root@ndw:~#
root@ndw:~# mkdir -p /etc/yunohost/hooks.d/custom_dns_rules/
root@ndw:~# nano /etc/yunohost/hooks.d/custom_dns_rules/01-vodafone
root@ndw:~#

root@ndw:~# yunohost dyndns update
Info: No updated needed.

root@ndw:~# dig TXT ndw.nohost.me

; <<>> DiG 9.11.5-P4-5.1+deb10u7-Raspbian <<>> TXT ndw.nohost.me

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32042

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 512

;; QUESTION SECTION:

;ndw.nohost.me. IN TXT

;; ANSWER SECTION:

ndw.nohost.me. 3600 IN TXT “v=spf1 a mx -all”

;; Query time: 47 msec

;; SERVER: 8.8.8.8#53(8.8.8.8)

;; WHEN: Tue Jul 19 19:27:14 BST 2022

;; MSG SIZE rcvd: 71

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