[dns-operations] Trustworthiness of PTR record targets

Jim Reid jim at rfc1035.com
Tue Mar 4 10:20:41 UTC 2014

On 3 Mar 2014, at 17:26, Stephen Malone <Stephen.Malone at microsoft.com> wrote:

> 1.       In general, can I trust PTR records? Is ownership of the target domain validated at setup time by ISPs, and if yes, how is this done?

Define what you mean by "trust" and "validate". For bonus points, define "ownership".

> 2.       If ownership of PTR targets is not routinely validated, is there a risk that the target domain could be blacklisted by anti-spam providers?

Again, please define "validate".

AFAICT organisations like Spamhaus don't care about PTR records at all. Addresses get blacklisted because they send spam or are open mail relays or are known to be in prefixes used for residential customers or.... Whatever names may be associated with those addresses are unlikely to matter, regardless of what validation is done or not done.

If you want to know what anti-spam organisations do with PTR records, I suggest you ask them directly.

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