From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 6 Nov 2014 20:12:48 +0100 From: Steffen Nurpmeso To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Message-ID: <20141106191248.Lx0kZAYi%sdaoden@yandex.com> References: <64562eef8a41a3bf4522cd750ac9d1a5@quintile.net> <20141031130919.PTgJzDSl%sdaoden@yandex.com> <00f41dd88b47a3c64637a4e184cbc332@ladd.quanstro.net> <20141031180930.b3WeLqGt%sdaoden@yandex.com> <20141105181920.r9S5I4BQ%sdaoden@yandex.com> <409298f02a8624e94fa9d7bc8c979921@ladd.quanstro.net> In-Reply-To: <409298f02a8624e94fa9d7bc8c979921@ladd.quanstro.net> User-Agent: s-nail v14.7.8-69-gf8bdb20 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Subject: Re: [9fans] Setting up Mail in Acme on the Raspberry Pi. Topicbox-Message-UUID: 243edd92-ead9-11e9-9d60-3106f5b1d025 erik quanstrom wrote: |On Wed Nov 5 13:20:02 EST 2014, sdaoden@yandex.com wrote: |> Anthony Sorace wrote: |>|> I've been looking through the documentation and |>|> the 9fans archive but I can't get a clear answer on |>|> what to replace localhost.localdomain with. |>| |>|If the recipient's mail server is being strict (but within |>|the bounds of the RFCs), that name is expected to be |>|the real, externally-resolvable DNS name of the |>|system you're sending from. The RFCs used to be more |>|lax on that point, and some servers still are, but you |>|shouldn't assume you'll be able to send to arbitrary |>|endpoints unless you satisfy that. |>=20 |> gmail.com shouldn't care at all, so it must be his own SMTP server. |> (All i know in respect to this is Yandex.(ru|com), which requires |> that the hostname in the SMTP FROM:<> command _is_ a Yandex |> address, i.e., _no mismatch_ with _who_ you claim to be, which is | |that's not what anthony claimed. he said that if you say | HELO example.com |that the following must be true |(a) dns return an a record for the query example.com, and Yes -- i think (or say, i'm sure that) gmail.com doesn't take care for that at all. Neither does Yandex. (Never tried any other free mail provider, i think they all depend on user authentication.) |(b) the ip returned must have a ptr record pointing to example.com |(this is less enforced these days due to the difficulty of \ |maintaining pointer |records.) ..So reverse lookups don't even come into play here. I'm no longer sure wether old-school really hates not to be able to perform sender verification via DNS, today a lot of pretty prominent people use those providers themselve. |i think this is compatible with what you're saying. this doesn't make |sense to me. i don't do this: | |> why i had to invent a *smtp-hostname* variable for the mailer |> i maintain in order to address the SMTP FROM:<> content directly: | |perhaps you're conflating the envelope with the message? Puh Erik, maybe -- you know, i'm a boche :) Flying over an official document is the maximum i can handle, just enough to hammer the most important facts into some long-time cells, so please excuse possible distortion of terms. Indeed, looking into RFC 5321 (i have it even in my arena): o The domain name given in the EHLO command MUST be either a primary host name (a domain name that resolves to an address RR) or, if the host has no name, an address literal, as described in Section 4.1.3 and discussed further in the EHLO discussion of Section 4.1.4. o The reserved mailbox name "postmaster" may be used in a RCPT command without domain qualification (see Section 4.1.1.3) and MUST be accepted if so used. So huch! SMTP communication how it actually happens in between me and the public mail providers is invalid, evil and yuck. I think i just wanted to add some value to what Anthony said. Regarding *smtp-hostname*: i think one cannot expect from what i call a normal user to understand just about anything regarding any protocol etc. internals -- for no other reasons but missing context information and maybe add lack of interest. In fact, like i said above, the same is true for me. Given that this BSD Mail derivative already has a variable called *hostname*, and that BSD / Linux systems have a hostname(1) command (even though POSIX only specifies uname(1) and documents "the name of this node within an implementation-defined communications network"; but POSIX.. well) i decided to name the capability to overwrite the hostname that is used in the SMTP "MAIL FROM:<>" command *smtp-hostname* (but not that the manual is really user friendly sofar). So now i'm stuck with it. But since Matt uses Google the address used in "MAIL FROM:<>" cannot be the problem anyway, since Google doesn't care wether the addresses in the messages' From: header and the SMTP "MAIL FROM:<>" command match or not (the last time i tried; i admit that the Google message i've posted doesn't really make sense in this context; oops..). --steffen