Re: Eric Sunshine mail delivery failure
On 23/08, René Scharfe wrote: Eric, hope you see this reply on the list. Direct replies to sunsh...@sunshineco.com are rejected by my mail provider on submit in Thunderbird with the following message: Requested action not taken: mailbox unavailable invalid DNS MX or A/ resource record. And with this one when using their web interface: A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address failed: "sunsh...@sunshineco.com": no valid MX hosts found It seems web.de wants you to get an record before I'm allowed to send mails to you. Sounds crazy. Sorry about that. Time to find a better provider, I guess. :-( Just an A record would be enough. The issue is that mail.sunshineco.com has neither an A nor an record, it is a CNAME to sunshineco.com, which is invalid according to RFC2181. -- Sincerely, Johannes Löthberg PGP Key ID: 0x50FB9B273A9D0BB5 https://theos.kyriasis.com/~kyrias/ signature.asc Description: PGP signature
Re: Eric Sunshine mail delivery failure
On Sun, Aug 23, 2015 at 1:16 PM, Johannes Löthberg wrote: > On 23/08, René Scharfe wrote: >> Eric, hope you see this reply on the list. Direct replies to >> sunsh...@sunshineco.com are rejected by my mail provider on submit in >> Thunderbird with the following message: >> >>Requested action not taken: mailbox unavailable >>invalid DNS MX or A/ resource record. >> >> And with this one when using their web interface: >> >>A message that you sent could not be delivered to one or more of >>its recipients. This is a permanent error. The following address >>failed: >> >>"sunsh...@sunshineco.com": >>no valid MX hosts found >> >> It seems web.de wants you to get an record before I'm allowed to send >> mails to you. > > Just an A record would be enough. The issue is that mail.sunshineco.com has > neither an A nor an record, it is a CNAME to sunshineco.com, which is > invalid according to RFC2181. Interestingly, the default configuration for all domains managed by this service provider is for the mailhost to be a CNAME. While the restriction in section 10.3 of RFC2181 makes sense as a way to avoid extra "network burden", in practice, email services seem to be pretty relaxed about it, and follow the CNAME indirection as needed. I suppose it's possible that web.de is being extra strict (although it seems that such strictness would be painful for its users), or this could just be a temporary DNS lookup failure. It's hard to tell based upon the errors René reported. I did change the CNAME to an A just in case, though who knows how long it will take for the change to propagate over to web.de's server. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Eric Sunshine mail delivery failure
On Sun, Aug 23, 2015 at 2:36 PM, Elia Pinto wrote: > Il 23/Ago/2015 20:26, "Eric Sunshine" ha scritto: >> On Sun, Aug 23, 2015 at 1:16 PM, Johannes Löthberg >> wrote: >> > Just an A record would be enough. The issue is that mail.sunshineco.com >> > has >> > neither an A nor an record, it is a CNAME to sunshineco.com, which >> > is >> > invalid according to RFC2181. >> >> Interestingly, the default configuration for all domains managed by >> this service provider is for the mailhost to be a CNAME. While the >> restriction in section 10.3 of RFC2181 makes sense as a way to avoid >> extra "network burden", in practice, email services seem to be pretty >> relaxed about it, and follow the CNAME indirection as needed. >> >> I suppose it's possible that web.de is being extra strict (although it >> seems that such strictness would be painful for its users), or this >> could just be a temporary DNS lookup failure. It's hard to tell based >> upon the errors René reported. >> >> I did change the CNAME to an A just in case, though who knows how long >> it will take for the change to propagate over to web.de's server. > Anyone can check Here https://dnschecker.org/#CNAME/Mail.sunshineco.com > It would fail with your change Interesting service; thanks for the pointer. However, since it's just querying a random set of DNS servers, it's not necessarily indicative of whether the change has actually propagated to the DNS server(s) answering web.de's mail server's queries. Local configuration (TTL's, etc.) on those servers or anywhere in between, as well as network conditions, could impact propagation to an unknown degree. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Eric Sunshine mail delivery failure
On Sun, Aug 23, 2015 at 2:48 PM, Eric Sunshine wrote: > On Sun, Aug 23, 2015 at 2:36 PM, Elia Pinto wrote: >> Il 23/Ago/2015 20:26, "Eric Sunshine" ha scritto: >>> I did change the CNAME to an A just in case, though who knows how long >>> it will take for the change to propagate over to web.de's server. >> Anyone can check Here https://dnschecker.org/#CNAME/Mail.sunshineco.com >> It would fail with your change > > Interesting service; thanks for the pointer. However, since it's just > querying a random set of DNS servers, it's not necessarily indicative > of whether the change has actually propagated to the DNS server(s) > answering web.de's mail server's queries. Local configuration (TTL's, > etc.) on those servers or anywhere in between, as well as network > conditions, could impact propagation to an unknown degree. Also, the propagation time of the A record can be quite different from the point at which the CNAME record finally expires (based upon its TTL, which may differ dramatically from server to server), so the above CNAME query may continue to succeed long after the A record has propagated. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
