Hi Dan (or Russ, whoever is running the domain),
the MX Records, in detail it’s weight, ls flawed compared to John Levin’s RFC 7505:
host list.cr.yp.to
list.cr.yp.to mail is handled by 0 c.mx.list.cr.yp.to.
RFC 7505 (proposed standard):
1. Introduction
This document defines the No Service MX, informally called "null MX",
as a simple mechanism by which a domain can indicate that it does not
accept email.
….
If a domain has no MX records, senders will attempt to deliver mail
to the hosts at the addresses in the domain's A or AAAA records. If
there are no SMTP listeners at the A/AAAA addresses, message delivery
will be attempted repeatedly for a long period, typically a week,
before the sending Mail Transfer Agent (MTA) gives up. This will
delay notification to the sender in the case of misdirected mail and
will consume resources at the sender.
This document defines a null MX that will cause all mail delivery
attempts to a domain to fail immediately, without requiring domains
to create SMTP listeners dedicated to preventing delivery attempts.
Mail server complying with RFC 7505 will not be able to deliver mail to this domain (so my s/qmail does):
2015-09-01 07:48:38.457328500 new msg 28853882
2015-09-01 07:48:38.457359500 info msg 28853882: bytes 19080 from <feh@fehcom.de> qp 10301 uid 7005
2015-09-01 07:48:38.580199500 starting delivery 120: msg 28853882 to remote qmail@list.cr.yp.to
2015-09-01 07:48:38.580202500 status: local 0/10 remote 1/100
2015-09-01 07:48:40.395327500 new msg 28853881
2015-09-01 07:48:40.395354500 info msg 28853881: bytes 19080 from <feh@fehcom.de> qp 10300 uid 7005
2015-09-01 07:48:40.529473500 starting delivery 121: msg 28853881 to remote michael@hudsonstreet.us
2015-09-01 07:48:40.529477500 status: local 0/10 remote 2/100
2015-09-01 07:48:40.974605500 delivery 120: deferral: _Sorry,_I_couldn't_find_any_host_named:_list.cr.yp.to._(#4.1.2)/
2015-09-01 07:48:40.974642500 status: local 0/10 remote 1/100
As workaround; I included list.cr.yp.to in smtproutes:
list.cr.yp.to:c.mx.list.cr.yp.to
best regards.
—eh.
---
Dr. Erwin Hoffmann | FEHCom | http://www.fehcom.de | PGP Key-Id: 7E4034BE
the MX Records, in detail it’s weight, ls flawed compared to John Levin’s RFC 7505:
host list.cr.yp.to
list.cr.yp.to mail is handled by 0 c.mx.list.cr.yp.to.
RFC 7505 (proposed standard):
1. Introduction
This document defines the No Service MX, informally called "null MX",
as a simple mechanism by which a domain can indicate that it does not
accept email.
….
If a domain has no MX records, senders will attempt to deliver mail
to the hosts at the addresses in the domain's A or AAAA records. If
there are no SMTP listeners at the A/AAAA addresses, message delivery
will be attempted repeatedly for a long period, typically a week,
before the sending Mail Transfer Agent (MTA) gives up. This will
delay notification to the sender in the case of misdirected mail and
will consume resources at the sender.
This document defines a null MX that will cause all mail delivery
attempts to a domain to fail immediately, without requiring domains
to create SMTP listeners dedicated to preventing delivery attempts.
Mail server complying with RFC 7505 will not be able to deliver mail to this domain (so my s/qmail does):
2015-09-01 07:48:38.457328500 new msg 28853882
2015-09-01 07:48:38.457359500 info msg 28853882: bytes 19080 from <feh@fehcom.de> qp 10301 uid 7005
2015-09-01 07:48:38.580199500 starting delivery 120: msg 28853882 to remote qmail@list.cr.yp.to
2015-09-01 07:48:38.580202500 status: local 0/10 remote 1/100
2015-09-01 07:48:40.395327500 new msg 28853881
2015-09-01 07:48:40.395354500 info msg 28853881: bytes 19080 from <feh@fehcom.de> qp 10300 uid 7005
2015-09-01 07:48:40.529473500 starting delivery 121: msg 28853881 to remote michael@hudsonstreet.us
2015-09-01 07:48:40.529477500 status: local 0/10 remote 2/100
2015-09-01 07:48:40.974605500 delivery 120: deferral: _Sorry,_I_couldn't_find_any_host_named:_list.cr.yp.to._(#4.1.2)/
2015-09-01 07:48:40.974642500 status: local 0/10 remote 1/100
As workaround; I included list.cr.yp.to in smtproutes:
list.cr.yp.to:c.mx.list.cr.yp.to
best regards.
—eh.
---
Dr. Erwin Hoffmann | FEHCom | http://www.fehcom.de | PGP Key-Id: 7E4034BE