I don't know how often Yahoo updates that page, but it does change sometimes -- so it appears *somebody* there remembers to bump it every now and then. However, Yahoo!'s list doesn't include any IPv6 mailers, and I have to believe they have some in use. So two questions:
1) Anyone got any more elegant ideas for how to look up Yahoo! outbound mailers when building a whitelist for Postscreen?
2) Anyone got any ideas for how to find their IPv6 outbound mailers?
Re: Any better ideas for grabbing Yahoo's known SMTP servers?
Have you tried to look at whois and DNS records for these addresses? They might have something in common.
Also, you seem to be doing something that's really Yahoo's job. Did you try to bug them directly why they don't do it? (Would improve security or something?..) If they use third party cloud servers, it'd be really hard to guess it remotely.
> Yahoo! has always been problematic (no surprise) because unlike all the other big mailers that Postwhite queries, they don't expose the IP addresses of their outbound mailers via their SPF records.
SPF is intended for an other use case. It authenticates and given IP. Postwhite try to use SPF data bye reverse means so it's obvious limited.