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

> On Aug 20, 2017, at 1:32 PM, Stephan von Krawczynski <skraw at
ithnet.com> wrote:
> 
> On Sun, 20 Aug 2017 12:29:49 -0400
> KT Walrus <kevin at my.walr.us> wrote:
> 
>>> On Aug 20, 2017, at 11:52 AM, Stephan von Krawczynski <skraw at
ithnet.com>
>>> wrote:
>>> 
>>> On Sat, 19 Aug 2017 21:39:18 -0400
>>> KT Walrus <kevin at my.walr.us> wrote:
>>> 
>>>>> On Aug 18, 2017, at 4:05 AM, Stephan von Krawczynski
<skraw at ithnet.com>
>>>>> wrote:
>>>>> 
>>>>> On Fri, 18 Aug 2017 00:24:39 -0700 (PDT)
>>>>> Joseph Tam <jtam.home at gmail.com> wrote:
>>>>> 
>>>>>> Michael Felt <michael at felt.demon.nl> writes:
>>>>>> 
>>>>>>>> I use acme.sh for all of my LetsEncrypt certs
(web & mail), it is
>>>>>>>> written in pure shell script, so no python
dependencies.
>>>>>>>> https://github.com/Neilpang/acme.sh      
>>>>>>> 
>>>>>>> Thanks - I might look at that, but as Ralph
mentions in his reply -
>>>>>>> Let's encrypt certs are only for three months -
never ending
>>>>>>> circus.      
>>>>>> 
>>>>>> I wouldn't characterize it as a circus.  Once you
bootstrap your first
>>>>>> certificate and install the cert-renew cron script,
it's not something
>>>>>> you have to pay a lot of attention to.  I have a few LE
certs in use,
>>>>>> and I don't think about it anymore: it just works.
>>>>>> 
>>>>>> The shorter cert lifetime also helps limit damage if
your certificate
>>>>>> gets compromised.
>>>>>> 
>>>>>> Joseph Tam <jtam.home at gmail.com>    
>>>>> 
>>>>> Obviously you do not use clustered environments with more
than one node
>>>>> per service.
>>>>> Else you would not call it "it just works",
because in fact the renewal
>>>>> is quite big bs as one node must do the job while all the
others must be
>>>>> _offline_.
>>>>> 
>>>>> -- 
>>>>> Regards,
>>>>> Stephan    
>>>> 
>>>> I use DNS verification for LE certs. Much better since
generating certs
>>>> only depends on access to DNS and not your HTTP servers. Cert
generation
>>>> is automatic (on a cron job that runs every night looking for
certs that
>>>> are within 30 days of expiration). Once set up, it is pretty
much
>>>> automatic. I do use Docker to deploy all services for my
website which
>>>> also makes things pretty easy to manage.
>>>> 
>>>> Kevin
>>>> 
>>> 
>>> DNS verification sounds nice only on first glimpse.
>>> If you have a lot of domains and ought to reload your DNS for every
>>> verification of every single domain that does not look like a
method with a
>>> small footprint or particularly elegant.  
>> 
>> I don?t understand what you are trying to say. I have over 170 domains
that
>> I generate certs for automatically using the acme.sh script. It is all
>> automatic and requires no ?reload your DNS? by me. The script just
updates
>> the DNS with a record that Let?s Encrypt checks before issuing the
>> certificate. After Let?s Encrypt verifies that you can update the DNS
for
>> your domain with the record, the script removes the record.
>> 
>> This actually works much better than HTTP especially for domains like
for
>> email servers that don?t have an HTTP server deployed for them.
>> 
>> Kevin
> 
> You can't update a record without reloading configs in bind. I guess
you are
> using some other DNS service...
I use Cloudflare (free DNS) and DNS Made Easy (paid DNS). I would never run my
own DNS service except for communicating between my Docker services internally
(Docker has its own internal DNS for this and there are many pre-built docker
images to provide a public DNS service, if required). But, Let?s Encrypt
requires you update the public DNS used by the domains you are generating certs
for. If you run your own public DNS service (for your Dovecot domains), you
should pick one that has an API for updating the DNS records from a script like
acme.sh or simply write your own custom hook for acme.sh to use.

See this page for all the DNS services that acme.sh supports: 

https://github.com/Neilpang/acme.sh/tree/master/dnsapi
<https://github.com/Neilpang/acme.sh/tree/master/dnsapi>

Kevin

On 20.08.2017 19:50, KT Walrus wrote:
> I use Cloudflare (free DNS) and DNS Made Easy (paid DNS). I would never
> run my own DNS service except for communicating between my Docker
> services internally
I run my own nameservers for various reasons, not the least of them
being DNSSEC. My zones' signing keys never leave my hands.
> If you run your own public DNS service (for your Dovecot domains), you
> should pick one that has an API for updating the DNS records from a
> script like acme.sh or simply write your own custom hook for acme.sh
> to use.
Nameservers like BIND or Unbound can use text based config files (zone
files), which can be generated on the fly with scripts. Add "rndc
reload" to the mix, and changes can be made instantaneously, without any
special APIs.

What can be a bother is when TTL values are set too high and changes in
the zones take too long to propagate, but that's a general issue, and
when running your own nameservers you can set these values as low as you
require.

-Ralph

P.S.: All this sure is interesting, but way off-topic in regards to
Dovecot. ;-)

I already have bind setup to allow DHCP to update.  Sometimes I need to
tweak things so I use nsupdate.  No 'rndc reload' required.
nsupdate.txt:
delete Zeratul.lan.example.com A
send
delete 90.6.168.192.in-addr.arpa PTR
send
add Zeratul.lan.example.com 902 A 192.168.6.89
send
add 89.6.168.192.in-addr.arpa 902 PTR Zeratul.lan.example.com
send
Command:
nsupdate -k /etc/named/DHCP_UPDATER.key nsupdate.txt

This could be used for a TXT record.

Bill

On 8/20/2017 3:59 PM, Ralph Seichter wrote:
> On 20.08.2017 19:50, KT Walrus wrote:
>
>> I use Cloudflare (free DNS) and DNS Made Easy (paid DNS). I would never
>> run my own DNS service except for communicating between my Docker
>> services internally
> I run my own nameservers for various reasons, not the least of them
> being DNSSEC. My zones' signing keys never leave my hands.
>
>> If you run your own public DNS service (for your Dovecot domains), you
>> should pick one that has an API for updating the DNS records from a
>> script like acme.sh or simply write your own custom hook for acme.sh
>> to use.
> Nameservers like BIND or Unbound can use text based config files (zone
> files), which can be generated on the fly with scripts. Add "rndc
> reload" to the mix, and changes can be made instantaneously, without
any
> special APIs.
>
> What can be a bother is when TTL values are set too high and changes in
> the zones take too long to propagate, but that's a general issue, and
> when running your own nameservers you can set these values as low as you
> require.
>
> -Ralph
>
> P.S.: All this sure is interesting, but way off-topic in regards to
> Dovecot. ;-)