ERROR:5.7.1:550 Mail Refused - DOMAIN_OR_IP_GOES_HERE -
See http://security.rr.com/mail_blocks.htm#subscription
This error message indicates that the sending domain has had, in
the past, a reputation for subscription abuse, a reputation that
may continue today. This reputation was sufficient for Road
Runner Security to take the step of refusing email from the
domain or network mentioned in the error message.
Subscription abuse is more commonly known as 'Mailing List
Forgery'. This often occurs with mailing lists that do not
follow the best practices of confirmed opt-in when
establishing their subscriber lists. Mailing lists requiring
confirmed opt-in signups will go through the following three
steps each time a new address is added to the list:
- A new subscriber will indicate a desire to sign up to
receive a list's mailings, and will provide a valid email address
to receive that list's mailings.
- The list owner will send a confirmation email to the signed
up address. This confirmation email will ask the owner of that
email address to verify that he/she signed up for this list by
replying to the confirmation email or perhaps clicking on a URL
in the confirmation email.
- Only after confirmation is received by the list owner will
the address be added to the mailing list.
Ideally, the list owner will also maintain records of these
transaction, to include copies of the signups and the
confirmations, with dates and times that they were received.
Additionally, the owner of the subscribed address may request
to be removed from the list at any time, and the list owner
will honor the request promptly.
Mailing lists that are less strict with their practices of adding
new subscribers are sometimes known as "single opt-in", "opt-in",
or "opt-out" mailing lists. Road Runner defines these terms as
follows:
- single opt-in or opt-in - These lists will
not add new subscribers unless they receive a request to do so
from somewhere, such as a webpage signup or an email. The new
address will start receiving email from the mailing list
immediately. The better of the single opt-in lists will have
the method or methods avaible for unsubscribing prominently
displayed in each mailing list email, and will honor unsubscribe
requests promptly..
- opt-out - These lists add subscribers from any
source available. They may advertise a method for unsubscribing
from the list, and they may even honor unsubscribe requests, but
given their typical methods of building their lists, their email
is more often than not unsolicited by the recipient.
Both of these types of lists are easy targets to use to abuse
unsuspecting recipients.
Single opt-in lists become vectors for abuse of Road Runner
customers in those situations where our customers get signed up,
without their prior knowledge, to one, ten, or any number of
mailing lists by someone wishing to cause our customers harm.
While a mailing list owner would still have proof that someone
asked for the address to be signed up to a given list, without
confirmation of the signup, this proof is dubious at best.
While single opt-in is not the best way, in our judgement, to
manage a mailing list, is it superior to opt-out lists. The
building of a mailing list with addresses gleaned from any
source available, including in some cases "brokers" who sell or
rent lists of harvested addresses, practically guarantees that
any mail sent to that list will be unsolicited by an overwhelming
majority of the recipients. Those who manage opt-out lists may
say, "Well, the recipients can just hit delete" or they may claim
to have working unsubscribe links in the email that they honor
promptly, but that is simply not good enough for Road Runner or
its customers. Both of these approaches put the burden and the
cost for managing list membership on Road Runner and its
customers, rather than where it belongs, with the owner of the
list. No Road Runner subscriber should ever be forced to
"unsubscribe" from a mailing list that he or she did not
subscribe to in the first place. Permission of new subscribers
must be fully verified before mailings commence.
A good source of more information on the best practices for
mailing list management can be found at
http://www.mail-abuse.com/an_listmgntgdlines.html. Echoing
the messager in that document, Road Runner calls on mailing list
managers to understand that email communication is about
conSENT, not conTENT. Road Runner is interested in making
sure that its customers receive all of the email that they signed
up to receive, and none of the email that they did not sign up
for.
Requesting Removal Of A Block For Subscription Abuse
You can submit a 
