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Comment by nathancahill | Hacker News Reader

How does this apply to email delivery? The biggest factor is having a "clean" IP address. Do these eventually become prohibitively expensive? Does email protocols switch to IPv6 and stop considering address reputation?

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Currently as only a handful of providers even support receiving IPv6 mail and due to spammers still using IPv4, we don't know yet. Usually /64 is considered for reputation in abuseipdb.

Another fact is gmail which supports IPv6 requires a PTR pointing back to the domain the mail is sending.[1] Currently a lot of providers which gives IPv6 does not support adding PTR records for IPv6, because it is handled differently than IPv4. This has led to lot of people defaulting to IPv4 when sending mail.[2]

[1] https://support.google.com/mail/answer/81126

[2] https://google.com/search?q=ipv6+gmail+ptr

I think lots of these schemes use each /64 prefix as a single unit for reputation purposes.

With email deliverability the key factor is now domain name reputation and less ip.

I never considered that it could be that way. That would be really nice: new domain, new reputation. Domains cost money, so that's good against spammers in general. And it's good for me, because my domains never sent any spam.

But alas, no, that's not the state of things.

Anything changed recently? I got into quite some issues when migrating my mail server a few years ago to a new host, which led to the need to change the server's IP address.

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