dovecot - Aug 2017 - is a self signed certificate always invalid the first time?

On 8/11/2017 1:29 PM, Ralph Seichter wrote:
> On 11.08.2017 11:36, Michael Felt wrote:
>
>> This is what Ralph means when he says "have been running a CA for
>> 15+ years" - not that he is (though he could!) sell certificates
>> commercially - rather, he is using an initial certificate to sign
>> later certificates with.
> Actually, I do sell certificates to my customers. :-) In small numbers,
> and only for servers to which I have administrative access.
So, not really "selling", but an additional
service.
> I created a
> root CA and two intermediate CAs (one each for client and server certs,
> respectively).
>
> It would be great to have my CAs added to Mozilla's NSS root
certificate
> store, but alas, the effort to get there is massive. Where possible, I
> will add my CA certs to the customers' keystores. I also made my CA
> certs available for public download, so tech-savvy users can import the
> CA certs manually.
>
>> Again, technically, there is no difference in a self-signed 2048-bit
RSA
>> key, and one signed by a "major" CA. However, in the
"ease of use" there
>> may be major differences.
> In 2015 I rolled out an updated CA which I have used ever since, with
> 4096 bit keys for root and intermediary CA certs. I also only generate
> 4096 bit keys for servers these days, so my cert chain is
"stronger"
> than those of some commercial CAs. Also, it is good to know that these
> certs have never been touched by anybody but myself. I even install my
> own CA cert chain on my iOS devices.
>
>> And, Ralph, I salute you. I have never been able to be disciplined
>> enough to be my own CA.
> I encourage you to look into the subject again.
I actually have been, which is why I could give a near sensible reply. 
Thanks for the encouragement!
> With the advent of Let's
> Encrypt, free certs for the masses have become a thing, but if you need
> more than 3 months validity, want to create certs for Intranet-devices
> (routers, local servers), or just want maximum control over all certs,
> setting up your own CA is rewarding. While you're at it, no gentleman
> should not be without DNSSEC, DKIM and DANE these days. ;-)
I should know all three, but, sadly, only one: two things to add to my 
list of things to research.
> -Ralph

On Fri, August 18, 2017 5:02 pm, Michael Felt wrote:
> On 8/11/2017 1:29 PM, Ralph Seichter wrote:
>>> And, Ralph, I salute you. I have never been able to be disciplined
>>> enough to be my own CA.
>> I encourage you to look into the subject again.
>>
> I actually have been, which is why I could give a near sensible reply.
> Thanks for the encouragement!
>
>> With the advent of Let's
>> Encrypt, free certs for the masses have become a thing, but if you need
>> more than 3 months validity, want to create certs for Intranet-devices
>> (routers, local servers), or just want maximum control over all certs,
>> setting up your own CA is rewarding. While you're at it, no
gentleman
>> should not be without DNSSEC, DKIM and DANE these days. ;-)
> I should know all three, but, sadly, only one: two things to add to my
> list of things to research.

I have been reading this with some interest (while trying to migrate
Dovecot, Postfix etc..)

BUT, for a public web server where https is becoming mandatory, I'd still
need a certificate from a recognized publisher, to avoid users geting
'warnings', is that so ?

(I'm currently using self issued for both mail and web)

thanks,

V

On 8/18/2017 9:12 AM, voytek at sbt.net.au wrote:
> On Fri, August 18, 2017 5:02 pm, Michael Felt wrote:
>> On 8/11/2017 1:29 PM, Ralph Seichter wrote:
>>>> And, Ralph, I salute you. I have never been able to be
disciplined
>>>> enough to be my own CA.
>>> I encourage you to look into the subject again.
>>>
>> I actually have been, which is why I could give a near sensible reply.
>> Thanks for the encouragement!
>>
>>> With the advent of Let's
>>> Encrypt, free certs for the masses have become a thing, but if you
need
>>> more than 3 months validity, want to create certs for
Intranet-devices
>>> (routers, local servers), or just want maximum control over all
certs,
>>> setting up your own CA is rewarding. While you're at it, no
gentleman
>>> should not be without DNSSEC, DKIM and DANE these days. ;-)
>> I should know all three, but, sadly, only one: two things to add to my
>> list of things to research.
>
> I have been reading this with some interest (while trying to migrate
> Dovecot, Postfix etc..)
>
> BUT, for a public web server where https is becoming mandatory, I'd
still
> need a certificate from a recognized publisher, to avoid users geting
> 'warnings', is that so ?
>
> (I'm currently using self issued for both mail and web)
Above - Ralph added:
> I also made my CA
> certs available for public download, so tech-savvy users can import the
> CA certs manually.
Depending on your site-popularity (aka number of "random" users) you 
could also instruct them how to access your signing key. Once they had 
that, they would auto-magically, recognize any other keys you signed 
with your CA "roots".

In other words, if the work to you to instruct users to use your CA is 
more expensive than using a commercial CA - save money and use a 
commercial CA. Before spending any money on a commercial CA - look at 
alternatives such as Let's Encrypt. I am also looking at 
http://www.cacert.org/ (That might be something for you Ralph!)
>
> thanks,
>
> V

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On Fri, 18 Aug 2017, voytek at sbt.net.au wrote:
> BUT, for a public web server where https is becoming mandatory, I'd
still
> need a certificate from a recognized publisher, to avoid users geting
> 'warnings', is that so ?
As Michael wrote already, it's the same vor all SSL certificates, because 
the underlying mechanism is the same.

- -- 
Steffen Kaiser
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On 18/08/2017 17:12, voytek at sbt.net.au wrote:
> BUT, for a public web server where https is becoming mandatory, I'd
still
> need a certificate from a recognized publisher, to avoid users geting
> 'warnings', is that so ?
> 
> (I'm currently using self issued for both mail and web)
> 
> thanks,
> 
> V
It depends on what you're uses are, self signed certs are OK for
smtp/pop3/imap, since most people are just concerned with "encryption"
in that case, but a different story if its web content, in particular,
shopping carts and the like, If you have clients content, definitely use
a real cert, maybe in 10 years letsencrypt might make the grade, but
until every bit of software and OS supports it and they offer insurance
levels like the bi boys do, you might as well be using a self signed
cert,  comodo are pretty cheap with basic insurance level on even the
most basic of their offerings. Do your research, though if using a paid
service, since some others are soon to be un-trusted. 

-- 
Kind Regards, 

Noel Butler 

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On 18.08.2017 09:12, voytek at sbt.net.au wrote:
> for a public web server where https is becoming mandatory, I'd still
> need a certificate from a recognized publisher, to avoid users geting
> 'warnings', is that so ?
For a certificate to be reported as "valid", an unbroken chain of
cryptographic signatures is required. Browsers are released with a set
of Root CA and Intermediate CA certificates, as are operating systems.
Some use the Mozilla CA Certificate Store[1], for example, others come
with their own CA stores, like macOS[2].

[1]
https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/
[2] https://support.apple.com/en-us/HT202858

Unless your web server certificate's signature chain originates from one
of the CAs delivered with a web browser or OS, the end user connecting
to your site will either have to manually add the required CAs, or add
your server certificate, or be presented with a warning/error message.

One could argue that relying on certificate stores is placing personal
security concerns in other people's hands. Of course, it would be a
potentially funny thing to try and verify the validity of your online
banking server's certificate by asking them to send you a letter
containing the certificate fingerprint...

-Ralph