Registration of Underscored and Globally Scoped 'for sale' DNS Node Name

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Table of Contents

1. Introduction

Well established services [RFC3912][RFC9083] exist, to find out if a domain name is registered or not. But the fact that a domain name exists does not exclude the possibility to obtain it, because it may be up for sale.¶

Some registrars and various other parties offer (payed) mediation services between domain name holders and interested parties, but for a domain name that is not for sale, such services are a waste of money and time.¶

This specification defines a simple universal way to find out if a domain name, even thouh it is taken, might be obtained nevertheless. It enables a domain name holder to add a reserved underscored node name [RFC8552] in the zone, indicating that the domain name is actually for sale.¶

The TXT record RRtype [RFC1035] that is created for that purpose MAY contain a pointer, such as a URI [RFC8820], to allow an interested party to find information or to get in touch and engage in further arrangements.¶

With due caution, this information can also be incorporated in the automated availability services, so that when the domain name is checked for availabilty, the service can also indicate it is for sale, including a referral to the selling party's information.¶

2. Rationale

There are undoubtedly more ways to address this problem space. The reasons for the approach defined in this document are primarly accessibility and simplicity. The indicator can be easilty turned on and off at will and more over, it is available right away and does not require major changes in existing services. This allows for a smooth introduction of the concept.¶

3. Convention

4. Examples

_for-sale.example.com. IN TXT "https://example.com/forsale.html"

_for-sale.example.com. IN TXT "mailto:owner@example.com"

_for-sale.example.com. IN TXT "tel:+1-201-555-0123"

_for-sale.example.com. IN TXT "I'm for sale: info [at] example.com"

_for-sale.example.com. IN TXT "<script>alert('H4x0r')</script>"

5. IANA Considerations

IANA has established the "Underscored and Globally Scoped DNS Node Names" registry [RFC8552][IANA]. The underscored node name defined in this specification should be added as follows:¶

             +-----------+--------------+-------------+
             | RR Type   | _NODE NAME   | Reference   |
             +-----------+--------------+-------------+
             | TXT       | _for-sale    | TBD         |
             +-----------+--------------+-------------+

6. Privacy Considerations

There is a risk of data scraping, such as email adresses and phone numbers.¶

7. Security Considerations

One use of the TXT record type defined in this document is to parse the content it contains and to automatically publish certain information from it on a website or otherwise. There is a risk involved in this, when the domain owner publishes a malicious URI or one that points to improper content. This may result in reputational damage for the party parsing the record.¶

Even worse is the scenario where the content of the TXT record is not validated and sanitized sufficiently, opening doors to XSS attacks among other things.¶

Therefore it is RECOMMENDED that any parsing and publishing is done with utmost care.¶

There is also a potential risk that this method is abused as a marketing tool, or to otherwise lure individuals into visiting certain sites or other forms of contact, without the intention of actually selling the particular domain name. It is therefore recommended that this method is primarily used by professionals who are sufficiently alert and aware.¶

8. Implementation Status

The concept described in this document is in use with the .nl ccTLD registry.¶

[note to editor: please remove this section before publication]¶

9. Acknowledgements

The author would like to thank Thijs van den Hout, Caspar Schutijser and Melvin Elderman for their valuable feedback.¶

Author's Address