Re: [swinog] Mail to CNAME a thing?

Cheers Jeroen, > If you are anti-spam, don't bother checking this (dom.com A); anybody > who wants to receive mail will have an MX, if not, let them join the > 2000s... There are actually quite a few (definitely more than white noise) senders that don't have MX, and only use A records. Many of t

Re: [swinog] Mail to CNAME a thing?

On 2018-02-19 12:57, Markus Wild wrote: > Hi there, > > I've just come across a weird mail reception problem of some mails from > Microsoft. Our servers insist that > a specified MAIL FROM address can be resolved correctly, and this usually > boils down to the following checks > on the domain-p

Re: [swinog] Mail to CNAME a thing?

Short update on this problem, which should be fixed by now: - I was able to reach the responsible team, and they answered very quickly. I was positively surprised! - They confirmed there's a problem with the zone content on their Dyn nameservers - They then added additional NS records on level ms

Re: [swinog] Mail to CNAME a thing?

there is actually one DNS service company providing Aname records .. basically a records with following an other A Record the getting notifyed when de A record changes and change the Aname record the very advantage is faster DNS resolve times and eliminating the need of Cname at all. and all

Re: [swinog] Mail to CNAME a thing?

Cheers Stephan, > I might be wrong but according to RFC 2821 it is ok to use a CNAME if > the target is resolvable to A or MX. > > 3.6 Domains > > Only resolvable, fully-qualified, domain names (FQDNs) are permitted > when domain names are used in SMTP. In other words, names that can >

Re: [swinog] Mail to CNAME a thing?

Hi I might be wrong but according to RFC 2821 it is ok to use a CNAME if the target is resolvable to A or MX. 3.6 Domains Only resolvable, fully-qualified, domain names (FQDNs) are permitted when domain names are used in SMTP. In other words, names that can be resolved to MX RRs or

Re: [swinog] Mail to CNAME a thing?

Hi Markus, it looks like Microsoft has configured their DNS zones in a creative way and I would expect them to come up with an RFC that justifies their creative way to "rape" DNS at a later time. For now, the way they have set it up looks unsupported to me and I doubt that they get any mails b

Re: [swinog] Mail to CNAME a thing?

Hello Ralph > [TL;DR] ;-) sorry about that, but it's not about an MX to a CNAME, it's about the domain part being resolved directly via a CNAME (kind of like having a domain-level CNAME to another domain, except _THAT_ isn't allowed due to shadowing NS and SOA records). With something like "a

Re: [swinog] Mail to CNAME a thing?

Am 19.02.2018 um 13:12 schrieb Ralph Krämer: > I am sure this is mentioned somewhere in one of the RFCs - but I currently > have no time to look this up. rfc1912 references in "CNAME records" section > Don't use CNAMEs in combination with RRs which point to other names > like MX, CNAME, PTR an

Re: [swinog] Mail to CNAME a thing?

Hi Markus, [TL;DR] ;-) a MX record pointing to a CNAME is generally not supported and a bad idea. I am sure this is mentioned somewhere in one of the RFCs - but I currently have no time to look this up. A MX should always point to a A record. kind regards Ralph - Am 19. Feb 2018 um 8:57

[swinog] Mail to CNAME a thing?

Hi there, I've just come across a weird mail reception problem of some mails from Microsoft. Our servers insist that a specified MAIL FROM address can be resolved correctly, and this usually boils down to the following checks on the domain-part of the email-address specified: - is there an MX?