Re:Adding a phone number to your Google account can make it ...
by drv on Thursday October 20, 2016 @05:03PM
(#12756140)
(Assuming you mean MailChimp)
I don't know anything about how MailChimp operates, but a quick search turns up this blog post about how to set up SPF records [1].
From there, you can get a list of which IPs MailChimp authorizes as a sender; following the SPF include directive, you can see they specify two IPv4 ranges, both of which are in class C space, so it seems unlikely that MailChimp has their own class A for SMTP senders.
[1]: https://blog.mailchimp.com/senderid-authentication-for-your-...
Re:Adding a phone number to your Google account can make it ...
by dunham on Thursday October 20, 2016 @07:15PM
(#12756976)
Yeah, we do something similar, although we send a much smaller amount of email than MailChimp.
Our admin runs about 10% of the outgoing mail through our DR site to keep google et al trained to accept emails from those IPs.
http://penguindreams.org/blog/how-google-and-microsoft-made-...
I've been meaning to write a follow up after I met some MailChip devs at a conference. They told me at MailChip they have to slowly spin up new servers, sending e-mail through them slowly so Google registers their new SMTP IPs.
The other thing they told me: MailChip owns a /A, and can therefore separately out their servers from even being remotely related to any spammy subnets (common problem on 'cloud' hosting).
I'm wondering if I heard/remember that correctly. I mean, a class A is huge and would be crazy expensive. I've been looking through websites on ASNs and am trying to figure out how to verify that info.