spam
Filtering Frequently Asked Questions
spam Mail Filtering FAQ
Q. What is
spam?
A. spam is the "junk
mail" of the Internet. It is unsolicited, meaning the recipients did
not sign up for the e-mail but received it anyhow.
Q. How do
spammers get e-mail addresses?
A. There are a number of ways that an
e-mail address can fall into the hands of a spammers. Lists of e-mail
addresses can be purchased, just like many bulk mailing companies
purchase lists of people's addresses. Giving out your e-mail address
through a form on a web page is another way, as is going into chat
rooms on the Internet. In some cases, Spammers have gotten ahold of
e-mail addresses by looking in the "From" field of a forwarded
message, which often contains the e-mail addresses of everyone who
has received the message.
Q. Does
Western Idaho Internet filter my e-mail?
A. Yes.
Q. Why does
Western Idaho Internet filter my e-mail?
A. To
prevent spam e-mail from being sent to Western Idaho Internet
customers and to reduce the possibility of our mail servers of being open to
DOS (Denial of Service) attacks caused by overwhelming the mail server with
junk mail.
Q. How does
my e-mail get filtered?
A.
Western Idaho Internet is provided with lists of mail servers from around
the world that have been known to send spam e-mail. These lists are
often referred to as Real-time Blackhole
Lists. When mail is sent to our servers, the incoming
messages are only blocked if they originate from a
server that shows up on one of the Real-time Blackhole Lists that
Western Idaho Internet is provided with.
Emails are
also verified as legitimate by making sure incoming mail has valid reverse DNS
on the return address, a valid return address, contain no malformed headers on
the message. Common spammer tricks are to fake these.
Q.
Why am I not receiving mail from some of the lists I have
subscribed to or a friend says they cannot email me.
A. Either the mail server they are
sending mail from is on a Real-time Blackhole List or
their mail has no valid reverse DNS on the return address, no valid return
address, malformed headers on the message.
When the
blocked server tries to connect with Western Idaho Internet's mail
server, we prevent them from sending us mail right then. You may still send
mail to servers that are on the Real-time Blackhole Lists.
Q. What are Real-time
Blackhole Lists (RBLs)
A. Real-time Blackhole Lists (RBLs) have
the IP addresses of e-mail servers that have been known to send
Spam. Most of the Spamming mail servers are a type of server called
an Open Relay Mail Server. These lists of "black listed" mail
servers are provided by a number of mostly nonprofit organizations
that are committed to ridding the Internet of Spam.
Q. Which Real-time
Blackhole Lists does Western Idaho Internet use?
A. Western Idaho Internet has chosen to use the
Real-time Blackhole Lists from one or more of the following
organizations:
- relays.osirusoft.com
- dialups.mail-abuse.org
- relays.mail-abuse.org
- blackholes.mail-abuse.org
Relays.osirusoft.com and relays.mail-abuse.org list Open Relay Mail
Servers that have sent Spam. As soon as the Open Relay is closed and
the RBL is informed, the mail server is tested, and if the
connection is truly closed, they are removed from the
RBL.
Dialups.mail-abuse.org is an RBL that lists
the IP addresses of dial-up, cable and DSL networks. Spammers will
sometimes use dial-up accounts from the listed networks to send
Spam. Mercury Network does not accept e-mail from the networks with
the blocked IP addresses.
Blackholes.mail-abuse.org lists closed
relay servers that send Spam. These could be mail servers whose sole
purpose is to Spam people or Internet Service Providers who do not
stop their customers from Spamming.
Q. How do Real-time
Blackhole Lists work?
A. The organizations that compile the
lists use a special web search tool that looks at e-mail servers to
see if it is an Open Relay Mail Server. The organizations
also research which of those mail servers send Spam, either on
purpose, or because other people can "high jack" the mail server to
send Spam.
Q. What is an
Open Relay Mail Server?
A. Open
Relay Mail Servers allow anyone from anywhere in the world,
connected to the Internet by any means, to send mail through a mail
server without having an e-mail account, or any other company or
customer account with the mail server.
Q. Why is
having an Open Relay Mail Server bad?
A. Spammers are the ones who most use
other servers to send mail, but Open Relay Mail Servers can also be
used to spread computer viruses. Spammers do not own the servers
they send most of their mail through, nor do they contribute any
money or labor to the upkeep of the servers. This amounts to theft
and is sometimes called "high-jacking" the server. Not only
does the spammer use a piece of equipment that is not theirs, but
they also hog network resources as the massive amounts of mail sent
through the servers require processing time and bandwidth.
Many of the
stories you have heard or read about "Denial of Service Attacks" are
spammers who use a company's mail server to mass e-mail the
Internet. So much mail is sent through at once that the mail server
finally crashes, disrupting a service that others pay for. And
mail sent through Open Relay Mail Servers is largely untraceable, so
even if you detect that your mail server has been used to spam
people, your chances of catching the person or people responsible is
slim to none.
Not all Open
Relay Mail Servers are guilty of sending Spam, but the potential is
there.
Q. Where can I get
more information?
A. http://www.mail-abuse.org/
http://www.mail-abuse.org/rss/.
http://mail-abuse.org/tsi/ar-what.html
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