Dave said:
I work from a home office. I'm a Comcast Subscriber and one of my clients
uses the external list zen.spamhaus.org to help them detect spam. Spamhaus
has a list called the Policy Blocking List (PBL) that states any IP address
in the Comcast range must use the Comcast outgoing mail server or it will be
blocked.
I normally use our company's outgoing mail server (provided by another ISP),
but when emailing this particular client my email is sent directly to their
spam bucket. Sending my email using my Comcast SMTP server rather than our
company's solves the problem.
I have set up another email account in outlook from which to send these
emails, but I'm looking for a way that Outlook will recognize this small
group of client emails needs to be sent using this alternate email account.
Instead of remembering to select the other email account on the pull down for
each message I sent, I want Outlook to make the selection based on the
contact I'm emailing.
When using the zen list, the PBL is included. That is a list of
dynamically assigned IP addresses, also referred to as a DUL (dynamic
user list). The zen list got seeded by the NJABL DUL (which is now dead
and SpamHaus took it over). If someone triggers on the zen blacklist
for your e-mails then that means you are sending from a mail host that
has been assigned a dynamic IP address. That is also what would happen
from an infected user's host running a mailer trojan. Legitimate mail
hosts should have a static IP address, not a dynamic one. So your
problem is an amateurish setup where the mail host is using a dynamic IP
address and probably doesn't have permission of the ISP to be running a
server, anyway. You need to get permission from your ISP to be running
a mail server, or you need to pay for a business account that permits
the customer to be running publicly accessible servers, and it should be
accessed using a static IP address. Else, you'll get nailed when using
the zen list.
If an e-mail service is using the zen blacklist then they must've
already checked that they are not bouncing a message between internal
hosts which then identify the sender's host IP address which will have a
dynamically assigned IP addresses. For example, I use Comcast.
Stupidly they bounce their e-mail in the last hop from another Comcast
user's host that will fire on the zen blacklist (from the PBL portion).
That is, a Comcast user sends me e-mail. They route it internally
rather than pass it through one of their outward-facing mail host. The
result is that the Received header won't show one of Comcast's mail
hosts (which has a static IP address) but instead shows the other
Comcast user's host (which is a dynamic IP address). That means if I
use the zen list that the pbl part of it will fire because the sender's
host was shown in the Received header rather than a Comcast mail host.
Because I do not want to tag every Comcast sender as a spam source, I
cannot use the zen list because all my e-mails will get tagged as spam.
Instead I have to use the sbl+xbl list (not the zen list which is
sbl+xbl+pbl). So it depends at what point the blacklist is being
implemented and also perhaps on how an ISP routes internal e-mails
between its customers as to whether the use of the zen blacklist is
proper.
If you are a Comcast user sending to another Comcast user, you will have
to educate that recipient that that they haven't a farking clue how the
zen blacklist works and they misconfigured their anti-spam software.
They will have to switch from the zen list to the sbl+xbl list. If
their anti-spam software doesn't let them configure this way then they
are using crap software and need to replace it, or disable using
blacklists altogether. Or your company's mail host is using a
dynamically assigned IP address (very stupid) so anyone using a DUL
blacklist is going to tag e-mails from your company as spam.
Your problem might by using a mail host that has a dynamic IP address.
Their problem might be using the zen blacklist when not appropriate for
their environment.
