Why Forwarding your Email is a BAD idea
Many people want to take advantage of "email forwarding" in which a
mail server auto forwards an incoming email to an email address on
that local server to a different domain on a remote server. Often
times a user will have an ISP email address (comcast, or verizon for
example), a freemail address (like gmail, yahoo or hotmail) and a work
email address. Instead of checking 2 or 3 different accounts the user
will setup forwards for 1 or more accounts into an account that he/she
will check, often times via a mobile device.
This is an extremely bad practice, and it is technically a broken
model for multiple reasons which will be covered below. The proper way
to do this (get email from multiple different accounts with different
providers) is to setup a pop3 or imap pull of email from one mailbox.
For example, suppose our user has 2 email accounts:
bestrealtor88@yahoo.com
bella.swan@bestrealty.net
Bella has had her yahoo account for 8 years and gets most of her email
from that account and she has her smart phone programmed to check her
yahoo account. Instead of setting up her Bella.Swan@bestrealty.net
account to FORWARD email to her yahoo.com account she should:
a. setup her smart phone to check both accounts OR
b. setup her yahoo account to login to her bestrealty.net account and PULL her email via pop3.
To understand why this is the case first we need to understand how
email forwarding works.
If Bella were to ignore our advice and forward
Bella.Swan@bestrealty.net to her yahoo account what might happen?
If Edward.Cullen@friendlyvampires.net decides to send Bella an email
to her Bella.Swan@bestrealty.net about an important contract, Bella
would expect to get the email in her yahoo.com inbox, but she ALSO
expects that the email will come FROM
Edward.Cullen@friendlyvampires.net and NOT Bella.Swan@bestrealty.net
when she looks at the email in her yahoo account.
So the email system that operates bestrealty.net email services
essentially has to impersonate friendlyvampires.net when it FORWARDS
the email to yahoo.com so that the FROM header is set correctly.
Meanwhile, Edward has had a problem with Spammers impersonating his
domain when they send spam. His service provider setup an SPF (Sender
Permitted From) record in DNS so that only the friendlyvampires.net
email servers are listed as authorized senders of email from
friendlyvampires.net.
The yahoo email servers will pay attention to this SPF record when
accepting email for Bella at her yahoo account. The yahoo servers may
decided to block or score as spam the forwarded email because
the emails servers for bestrealty.net ARE NOT listed in the SPF record
as authorized senders for email coming from @friendlyvampires.net.
Clearly Edward cant contact each of the thousands of people that he
emails and add any possible servers that might forward said emails he sends
to anyone and add SPF records for each possible forward.
This is why the combination of an email forward and a source (SENDING)
domain with an SPF record ALWAYS breaks. For source domains that DONT
use SPF records, the forwards may work (but generally be scored as
more likely to be spam) so end users get confused. Bella seems to
think the problem is with Edward, since "everyone else can send me
email" but the problem actually lies with Bella.
Lets look at another problem that forwarding causes:
Lets say Rosalie has the domain test.com. Rosalie sets up an email
forwarder for Rosalie@test.com to forward to her Rosalie2@hotmail.com.
The email service provider that runs test.com though has a big
problem. Rosalie expects that ANYTHING sent to Rosalie@test.com is
forwarded on - does the provider attempt to forward ALL email
including all the spam that she has been getting lately, or does it
try to filter the SPAM? Since Rosalie is only using the intermediate
email as a forward, she does not login to that account to set her spam
settings, or check her spam folder most likely on a regular basis. The
only reason she wanted to forward her email was to have only 1 mailbox
to check. Having to manage spam settings on multiple mailboxes and
track down where spam is trapped (if a legit message was snagged in a
filter) defeats the whole purpose of the forwarding for Rosalie.
Lets say Rosalie get 10 valid emails a day on average. For most email
addresses and/or domains that have been use for more than a year 10
SPAMs coming in for every legitimate email. This means that the
test.com email server is going to actually have to forward 100
additional SPAMs a day to hotmail or some lesser number depending on
how much they can filter out.
Of course the hotmail Mail Firewall sees this behavior (100 SPAMs a
day from the same sending machine) and quickly blacklists (refuses ALL
messages from) the test.com email server. Not only is the email server
that runs test.com seen as a SPAMMER, test.com is now seen as a SPAM
SOURCE. This means that the reputation of both Rosalie's domain and her
service provider is damaged - not good for Rosalie OR the operators of
the mail server she hosts her test.com domain at. Rosalie can always
get a new domain or try to get her domain off the blacklist, but for
the company that operates the mail servers that host her domain the
blacklisted ipv4 addresses of the mail server could cause thousands of
mails to be dropped or delayed and many hours to sort out with many
customers and domains affected.
Additionally, if Rosalie has setup a catch-all email address -
i.e. @test.com so that sales@, info@, jules@, etc all work and go to
her hotmail account via a forward then we all have an even bigger
problem. If a SPAMMER tries a dictionary attack against test.com - sending
hundreds or thousands of emails to made up addresses @test.com then
the test.com email service provider will be forwarding ALL of those
messages on to hotmail, which will have the server blacklisted within
minutes.
Suddenly Rosalie stops getting ANY email into her Hotmail account that
she expects from her forwarded account. Who does she call ? Well, she will
be lucky if she can actually get anyone from a large ISP
(Verizon/Comcast/Embarq, etc) or large mail provider (hotmail, gmail,
yahoo) to talk to. And even if she could she would get the no problem
here, must be on the other end response, because as far as that
provider is concerned, all they are doing is saving her the headache
of getting an additonal 110 SPAMs a day (her 100 SPAMs plus the 10
legit emails).
Remember, when one individual user tries to deal with large companies that
process millions of emails an hour, its impossible for them to really
care or worry much about a few legit emails that get blocked. Blocking
the massive SPAM inflow is much more important, because if their
customers get thousands of SPAMs each day, they would simply not use
and/or pay for their service.
So next Rosalie calls the provider of test.com to investigate the
problem on their side. The answer she will get is: "no problem here,
we see that hotmail.com is blocking our attempts to send email". The
provider may or may not be able to get hotmail.com to take action and
fix this. More often than not, this is very time consuming for the
providers to track down a human on the opposite side that is able to
fix the problem. So email remains broken, or in a state of flux
(sometimes works, sometimes does not, depending on whether hotmail
removes the blacklist after a period or not, and depending on how much
SPAM comes through the auto forward).
Finally, to avoid the forwarding of SPAM mess discussed above. most
providers (if they have any clue at all) will fully SPAM filter all
email BEFORE its forwarded, so they avoid getting blacklisted for
forwarding SPAM. This means that an email will take the following
path:
SENDER :: FORWARDER_FIREWALL :: FORWARDER :: RECIP_FIREWALL :: RECIPIENT
Either of the 2 firewalls - FORWARDER or RECIPIENT can possibly reject
a message due to it matching:
1. SPAM or SPAM-like content (often the case if you forward off color
jokes, or other chain letter type email)
2. VIRUS or SPYWARE
3. DANGEROUS file names or file contents (like a "cool" screensaver
you found)
4. LARGE FILE ATTACHMENTS (multiple photos for example)
Each of the firewalls will have different policies (support FORWARDING
firewall allows 20 MB attachments, but RECIPIENT firewall only allows
5 MB attachments because its a FREE ACCOUNT!)
Troubleshooting where the email was blocked wastes the time and
resources of each provider (FORWARDING and RECIPIENT) neither of which
will be sure where the problem really is unless they investigate
manually, which generates zero profits, only costs for the providers.
Many web hosts are now banning email forwarding to third party email
accounts, removing the capability all together. And the result for
these hosts is a serious decrease in spam complaints against their
servers. Richweb does not ban email forwarding just yet, but it is
inevitable that for most providers that forwarding email externally is
just too much trouble, and the benefits to everyone by turning it off,
far outweigh any benefits of having this so called "feature".