Well the DNC is pretty open about the fact that they were hacked, and there's implants on their servers, so clearly someone took control on the email server. The presence and accuracy of DKIM headers is solid evidence the emails are from the hackers, but not necessarily of their legitimacy. If they had complete control of the email server, then they would have access to the DKIM's private key, making it trivial to spoof emails.
So yeah, definitely from the email server, but that doesn't necessarily mean it's authentic. Though IMO it's likely authentic, the DNS as far as I know hasn't challenged the authenticity of any emails, and I were forging emails I'd make them a lot more damaging than what we've been given.
It's definitely been some time, but I noticed (personally verifying DKIM records) that a good chunk of the Podesta emails didn't pass. I'd have to dig out those exact emails again, unfortunately.
Edit: Huh, guess Wikileaks has a hard 40Mbit down limit for downloads, this might take a while.
Edit 2:
Not sure if this is due to time since leaks, and weirdness, but one such email I found was https://wikileaks.org/podesta-emails/emailid/41063
dkim.ValidationError: body hash mismatch (got xYeNHE1y7S7c90FEmj0Clvuu8UkskqNWL3LiuMxCrsc=, expected SFTNrt5rWQXzb3TEj9vxbo/FLGDSOiYFg+04PjFRv3A=)
While I'm finding valid headers, I'm finding a good portion of negatives too. I have to sort through the spam emails in his inbox first though (lots of irrelevant DKIM failures).Edit 3:
Just some numbers (which are definitely inflated from the spam emails I found, by how much I'm not sure):
root@ubuntu-512mb-nyc1-01:/mnt/volume-nyc1-01# cat output | wc -l
9981
root@ubuntu-512mb-nyc1-01:/mnt/volume-nyc1-01# cat totest | wc -l
28024
root@ubuntu-512mb-nyc1-01:/mnt/volume-nyc1-01# ls out/ | wc -l
50887
Edit 4 (and the last):The quick script thrown together to put numbers together, https://gist.github.com/Omeryl/c6cbe603721f5671b9056ca127399.... I don't have the time to go through and see how many of those messages are spam that are just failing to validate, etc. It's worth noting that some messages may be failing to validate because x= is past, etc, as well.
https://www.reddit.com/r/DNCleaks/comments/58v1if/dkim_verif...
This is a huge claim, and if you can verify it, it will be very big news in the (fairly dedicated and savvy) communities that follow this.
Additionally, it's possible to provide airtight evidence to demonstrate this huge claim.
> I'd have to dig out those exact emails again, unfortunately.
Something of this magnitude is probably worth the time.
I did write up a little bit below in a comment, before your post: