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Your mailbox
at Netfront is already protected
What is Spam ?
Spam is the common term for Unsolicited
Commercial Email (UCE), the Internet version
of junk mail. Unlike postal junk mail
where the sender has to pay for printing
cost and stamps for each delivery, Spammers
can send millions of emails per day on
a cable or DSL line at virtually no cost.
The only cost is your time to receive
and read those spams. Why
are there Spams ?
The shortcoming of the current Internet
e-mail architecture is that there is no
good and commonly available mechanism
to check against the identity of e-mail
senders, meaning that spammers can forge
to be anyone to send e-mail to any other.
How does Netfront filter
Spams ?
We have employed a very effective and
fast method
to filter spam, at the speed of 2-5
seconds to filter each e-mail.
First stage: the e-mail servers
calculate a digital signature of any e-mails
received, and use that signature to check
the number of copies of the same message
other ISPs have received. If that number
is exceedingly large (over a million)
and the e-mail is not in our white-list,
the e-mail is discarded immediately. This
is the Default Filter, which filters 95%
of spams with no loss of
legitimate e-mails.
Second stage: the e-mail server tries to guess
how likely a piece of e-mail being spam
and associate it with a numeric score.
The score is added to the header of
the e-mail. If you have tightened your
filter to levels Tightened, Intermediate,
or Aggressive, then the filter will
check that score and move likely spam
e-mails to a "spam" folder.
E-mails that pass through the filter
will be delivered to your normal inbox.
The "spam" folder can be accessed
via our webmail site http://webmail.netfront.net
How do I tighten my spam filter
?
The filter has three levels of aggressiveness
(Tightened, Intermediate and Aggressive).
The more aggressive the filter, the
more spams removed but the chance of
incorrectly picking legitimate e-mails
as spam slightly increases too. So you are suggested
to visit the "spam" mailbox
periodically to check if good e-mails
are filtered and adjust your filter
level accordingly. Also, the "spam"
folder will be counted as server disk
space used by your account, so please
clean it when necessary.
Are there other ways to use
the filter ?
Yes. If your e-mail client software
can filter e-mail based on its headers,
(e.g. Microsoft Outlook), you can configure
your e-mail client to do the filtering.
The score is represented by a header
line "X-Spam-Level:". More
"*" means the email is more
likely a spam. Normal email should have
"*"s less then 8.
To use this filtering method, you have
to set the spam filter to Default Filter
on our servers. This will make the
filter at stage 2 to
only guess the spam likeliness, add
it to the header, but not move anything
to the "spam" folder. You
can then use your e-mail client software
to take desired actions based on the
header lines. Is my privacy
protected ? Yes, because no other
people inspect the content of your e-mail,
and the e-mail servers only calculate and
inspect digital digests of e-mails but do
not look into the context of those
e-mails. Does the filter delay my e-mails
? The e-mail filtering action
will add 2-5 seconds delay to each e-mail.
How effective is this filter?
The figures below are for reference
only. It might not apply to your specific
situations.
- Default Filter
– Filtered 92% of spam at no loss of legitimate
e-mails
- Tightened Filter - Filters 96% of spam
and 0.1% of good e-mails
- Intermediate Filter - Filters 98% of
spam and 0.2% of good e-mails
- Aggressive Filter - Filters 99% of spam
and 0.4% of good e-mails
Is this service free?
This service is free for now. We will provide prior information if any charges shall be required.
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