Hi Viktor,

thanks for you remarks. There is still room for improvement.

I'll have an eye on it. Talked to Lutz.

Regards.
--eh. 


Am Montag, dem 25.09.2023 um 15:52 -0400 schrieb Viktor Dukhovni:
> On Mon, Sep 25, 2023 at 08:46:48PM +0200, Erwin Hoffmann wrote:
> 
> > one of my s/qmail users has problems with the TLSA/DANE record for
> > the
> > following domain:
> > 
> > * excalibur.iks-jena.de
> 
> That's the MX host of "iks-jena.de".  For which the DANE survey:
> 
>     https://stats.dnssec-tools.org/
> 
> shows no issues with the TLSA records vis-à-vis the corresponding
> certificate chains:
> 
>     https://stats.dnssec-tools.org/explore/?iks-jena.de
> 
> The only issue with the domain is its use of the deprecated DNSSEC
> algorithm RSASHA1(5) (more on this further below).
> 
> > Here, I get the settings:
> > 
> > $ dnstlsa excalibur.iks-jena.de  
> > Usage: [2], Selector: [1], Type: [1]  
> > 10f34e8f08e446cc26d7d591184b51cb83791c869cef388be5d5cb58e2927f7a  
> > Usage: [2], Selector: [1], Type: [1]  
> > 3c9762932ec8e6e52d4b37504f15d90a3fac9930e1058170372b3a4b0e068a43
> > 
> > where the root FP is ok, the MTA's not.
> 
> The TLSA RRset designates two DANE-TA(2) trust anchors, the first of
> which is the one currently in use, the second recently retired:
> 
>  1. subject=C = DE, ST = Thuringia, L = Jena, O = IKS Service GmbH,
> OU = IKS CA, CN = CA der IKS Service GmbH (SIGN) 2023, emailAddress =
> [email protected]
>     issuer=C = DE, ST = Thuringia, L = Jena, O = IKS Service GmbH, OU
> = IKS CA, CN = CA der IKS Service GmbH (SIGN) 2023, emailAddress =
> [email protected]         notBefore=Dec 28 13:41:37 2022 GMT
>     notAfter=Jan 26 13:41:37 2025 GMT
> 
>  2. subject=C = DE, ST = Thuringia, L = Jena, O = IKS Service GmbH,
> OU = IKS CA, CN = CA der IKS Service GmbH (SIGN) 2022, emailAddress =
> [email protected]
>     issuer=C = DE, ST = Thuringia, L = Jena, O = IKS Service GmbH, OU
> = IKS CA, CN = CA der IKS Service GmbH (SIGN) 2022, emailAddress =
> [email protected]
>     notBefore=Jan  3 14:41:25 2022 GMT
>     notAfter=Feb  2 14:41:25 2024 GMT
> 
> Per all relevant DANE specifications, it is sufficient for either to
> match the certificate chain.
> 
> > Given the remarks in RFC 7672 section 3.1.2, I feel a bit
> > uncomfortable
> > about it. 
> 
> If the qmail DANE implementation in question has problems with this
> domain, the problem is with qmail, not the DANE TLSA records or
> presented certificates.
> 
> 
> On Mon, Sep 25, 2023 at 09:19:39PM +0200, Lutz Donnerhacke wrote:
> 
> > > * excalibur.iks-jena.de
> > 
> > As the admin of the server in question.  What's the problem?
> 
> As noted above, nothing wrong with DANE.  A DNSSEC algorithm rollover
> would however be prudent.  Many RedHat systems no longer support the
> SHA1 DNSSEC algorithms 5 and 7 and your domain is "insecure" for
> validating resolvers running on these systems.
> 

-- 
Dr. Erwin Hoffmann | www.fehcom.de
PGP key-id: 20FD6E671A94DC1E
PGP key-fingerprint:  8C6B 155B 0FDA 64F1 BCCE A6B9 20FD 6E67 1A94 DC1E

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