Hi,

> On 05 Apr 2016, at 11:16, Daniel Margolis <[email protected]> wrote:
> Could you go a bit into what you consider "mx indirection" and where you see 
> problems there? e.g. a specific problem statement. I'm not sure I follow.
> 
> To slightly paraphrase Binu's reply, I think one of the (if not the) key 
> challenges with SMTP STS is allowing the email domain to specify a routing 
> policy (and maybe also a security policy, as discussed with Chris up-thread) 
> regardless of whether it's also the email hosting domain.
> 
> I'm not clear on how TACK can be used here.

TACK isn't the right place to distribute information from. It's a TLS 
extension, it should be terse. My original idea was to use a SMTP extension 
along with required TACK-like authentication. The extension could send 
arbitrary information. As mentioned earlier, I'm not sure what the best way is 
to integrate this with STS.

> 
> One idea on how to use a CT-style append-only log is that you could use the 
> log itself as the source of policies, and the log server can sort of do 
> whatever it wants to for the log inclusion criteria (e.g. with CT the 
> inclusion criteria are "must be an EV cert", but that's very arbitrary; a 
> different log could include any policy served over validated HTTPS for any 
> domain, or you could have a log that includes policies seen by EFF's outbound 
> MTA--since the log is observable and append-only, it still feels a lot safer 
> to me to do this than to use Github for policy distribution).

Yes, I totally agree there. git was brought up in a discussion, we're not 
currently implementing anything in that direction. When we come back to this 
we'll see what's available from UTA etc. for us to use.

> I'm not sure about this intuition, though I only have a counter intuition. 
> For the hosted scenario, a provider could simply set up an HTTPS endpoint for 
> their client domains, use SNI, and fetch SSL certs for the client as part of 
> a hosting package. For the self-hosted scenario, is it considerably harder? 
> I'm not sure, but given how easy it is to set up a personal HTTPS endpoint 
> with Let's Encrypt, I don't really see why. Am I far off base?

While I see benefits to hosters, what I've seen from community projects like 
bettercrypto(.org) is there's a lot of misunderstanding on how to properly 
configure services, a lot of bad information sources around for sysadmins and 
barely any tooling to automate. Let's Encrypt now does automate on specific 
platforms and for specific daemons - we'll probably extend this to some degree 
for mail daemons in the future but there's also a lot of unwillingness among 
admins to use automation tools that require e.g. root. I feel that a lot of 
admins will reject going via HTTPS services just to serve mail in a secure 
fashion. I'm also not sure how willing software implementers will be to go this 
direction, but we'd better ask them.

Thanks,
Aaron

Attachment: signature.asc
Description: Message signed with OpenPGP using GPGMail

_______________________________________________
Uta mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/uta

Reply via email to