Date: Mon, 8 Sep 1997 09:05:21 -0700 (PDT) From: "Jonathan M. Bresler" <jmb> To: gurney_j@resnet.uoregon.edu Cc: hackers@hub.freebsd.org Subject: Re: spam and the FreeBSD mailing lists Message-ID: <199709081605.JAA08961@hub.freebsd.org> In-Reply-To: <19970907192536.54931@hydrogen.nike.efn.org> from "John-Mark Gurney" at Sep 7, 97 07:25:36 pm
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John-Mark Gurney wrote:
>
> Jonathan M. Bresler scribbled this message on Sep 7:
> > only the relay has to be contactable via TCP/IP.
> > not the "mail from:"
>
> no... your not correct... read what the rfc821 has to say about it:
> MAIL <SP> FROM:<reverse-path> <CRLF>
>
> This command tells the SMTP-receiver that a new mail
> transaction is starting and to reset all its state tables and
> buffers, including any recipients or mail data. It gives the
> reverse-path which can be used to report errors. If accepted,
can != must
> the receiver-SMTP returns a 250 OK reply.
>
> The <reverse-path> can contain more than just a mailbox. The
> <reverse-path> is a reverse source routing list of hosts and
> source mailbox. The first host in the <reverse-path> should be
should != must
> the host sending this command.
>
> two key sentences... a) "It gives the reverse-path which can be used to
> report errors." b) "The frist host in the <reverse-path> should be the
> host sending this command." basicly it states that the MAIL From must
> be a perfectly representable mail address to YOU... if this forces the
> person to add "@relay.host.name" at the end, then be it.. but it clearly
> states that if the recieving end doesn't accept it, they don't have to...
rfc1123 p 69 has a summary table of SMTP behavior for internet hosts
which in part reads:
| | | | |S| |
| | | | |H| |F
| | | | |O|M|o
| | |S| |U|U|o
| | |H| |L|S|t
| |M|O| |D|T|n
| |U|U|M| | |o
| |S|L|A|N|N|t
| |T|D|Y|O|O|t
FEATURE |SECTION | | | |T|T|e
-----------------------------------------------|----------|-|-|-|-|-|--
RECEIVER-SMTP: | | | | | | |
Support empty reverse path |5.2.9 |x| | | | |
Accept and recognize self domain literal(s) |5.2.17 |x| | | | |
Send error notification msg after accept |5.3.3 |x| | | | |
Send using null return path |5.3.3 |x| | | | |
Send to envelope return path |5.3.3 | |x| | | |
Send to null address |5.3.3 | | | | |x|
the reverse path may be empty,
else why must an empty one be supported.
null return path must be used in error notification msgs
which should be send to the envelope return path,
but may be sent elsewhere, Return-Path, for instance
admittedly, every SMTP sender must place "Canonicalized
domain names in MAIL, RCPT", but at least one of the lists
(questions) is for people that dont even know what an RFC
is. so, i have chosen to be more liberal in accepting
"mail from:" addresses especially in light of our policy
to allow mail to flow into news servers but not the reverse.
the idea is that a person reading news may send mail to
the lists from a misconfigured host which does not create
a valid "mail from"
>
> > two more bite the dust:
> >
> > Sep 7 18:18:31 hub sendmail[23726]: NOQUEUE: ruleset=check_relay, arg1=imsp015.netvigator.com, arg2=205.252.144.206, relay=root@localhost, reject=521 blocked.contact postmaster@FreeBSD.ORG
> > Sep 7 18:32:45 hub sendmail[24585]: SAA24585: ruleset=check_mail, arg1=<amish1@cyberamish.com>, relay=root@[205.164.68.2], reject=521 <amish1@cyberamish.com>... specially processed assorted meats? yuck!
>
> I like the last one.. :)
;)
jmb
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