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I use DSL and I can't send email, but I can receive
it.
Sending Outbound Email
Bell System DSL, Charter Cable, Cox Cable and other ISPs
are implementing "port 25 blocking", so you may have to
send OUTBOUND email through THEIR server. If this
happens to you, you will find you are receiving email,
but can not send email. You may get a message that your
outbound mail server can not be found or does not exist.
Since you are receiving email from that same mail
server, you can be sure that it does exist and can be
found. Since you can't SEND email out through it, your
mail program is simply returning this error message to
notify you that it couldn't send email using that mail
server.
When you SEND email: You can only SEND email OUT
through your Internet Access Provider's outbound (SMTP)
mail servers. You can not SEND email OUT through any
other mail servers except theirs. When you RECEIVE
email: You can continue receiving email at your domain
name with your current settings. You do not need to
change anything to continue receiving email at your
domain name. To SEND email, you must change your
OUTBOUND SMTP mail server, under "Account Server
Settings" in your mail program. SBCGlobal Business DSL
Customers
For SBCGlobal DSL customers, the exact setting depend on
your SBCGlobal service.
- Business DSL Customers have "dedicated" IP
Numbers.
- Residential DSL Customers have "dynamic" IP
Numbers.
For SBCGlobal Business DSL Customers with
dedicated IP Numbers:
Change your OUTBOUND SMTP mail server, under
"Account Server Settings" in your mail program.
- Specify SWBell's out bound SMTP server in your
outbound SMTP server Settings (smtp.SBCGlobal.net)
and
- Un-check the "my server requires authentication"
check box.
- Save, restart Outlook, click "Send and Receive"
and your email should go out.
Your mail should still go out "FROM" your domain
name, it just goes out through SBCGlobal mail
servers instead of WebHeadGroup.com's.
SBCGlobal Residential DSL Customers
For SBCGlobal Residential DSL Customers with dynamic IP
Numbers:
Change your OUTBOUND SMTP mail server, under "Account
Server Settings" in your mail program.
- Specify SWBell's out bound SMTP servers in your
outbound SMTP server Settings (smtp.SBCGlobal.net)
and
- CHECK the "my server requires authentication"
check box.
- Select "Log on using" and enter your
SBCGlobal.net email address and the corresponding
password. This is the user name and password you use
to access your DSL connection.
- Save, restart Outlook, click "Send and Receive"
and your email should go out.
Your mail should still go out "FROM" your domain
name, it just goes out through SBCGlobal mail servers
instead of WebHeadGroup.com's.
YES, Your Email Will Still Be "FROM" Your Domain Name
YES, when people receive your email, it will still be
"FROM" you at your domain name. The "FROM" and "REPLY
TO" addresses are informational settings in your mail
program, they do not result from the mail server you
send mail out through. (This is why you get spam and
viruses "FROM" people who really didn't send it to you.
NOTE: Some Internet Access Providers DO change your
FROM address. This is typically limited to the "Free" or
"Advertising Supported" ISP's such as NetZero and Juno.
They may change your FROM and REPLY TO addresses to your
email address with them to direct all return email
through your email account with their server since they
earn advertising revenue that way to. Commercial ISP's
do not normally do this, and SWBGlobal does not.
What's This All About?
"Port 25" is the "out-box" for your Internet Connection,
used to send out-bound email. Your computer connects to
"Port 25" of a mail server when it wants to send email.
You may have, in the past, used Port 25 to connect to
your own mail server hosted at WebHeadGroup.com, or at
another service provider.
Internet Access Providers have begun "Blocking Port
25". As a result, you can only connect to your access
provider's mail servers to SEND email out. In other
words, you can only send email out through their mail
servers. You can continue to receive email from your own
mail server, but you can't send email out through your
own mail server.
Many access providers do not inform their customers
of this change. Sometimes their technical support
personnel have not been notified either.
Why Block Port 25?
SBCGlobal and other Internet Service Providers are
blocking Port 25 to reduce spam and viruses.
- Spammers sign up for high speed Internet access
accounts (such as DSL and Cable) and run their own
mail server (smtp engine) to deliver their spam
messages. This smtp engine connects to each spam
recipient's mail server and delivers the spam
directly to the recipients mail server. The ISP can
not see the spam messages being delivered.
- When the ISP blocks Port 25, these smtp engines
can not connect to recipient's mail servers and can
not deliver spam messages. Instead, the spammer must
send mail out through the ISP email server. The ISPs
run mail server monitors to detect spammers so they
turn them off quickly. This can reduce the flow of
spam.
During the last year, "Commercial Viruses" have
infected hundreds of thousands of computers.
Commercial viruses are relatively new. They do not
disrupt your computer operations or do anything
"bad" to your computer. Many people do not even know
their computers are infected with these viruses.
Commercial Viruses let spammers connect up to the
infected computer and send spam messages out using
the infected computer. These infected computers are
referred to as "Zombies" in the industry. Zombies
have an "smtp engine" like the spammer programs and
send out spam the same way, by connecting directly
to the recipient's mail server.
The current Zombie programs can not send out spam if
Port 25 is blocked. If Zombie operators update their
programming to use the ISP's outbound mail server,
then operating the Zombies will be more difficult
and the Zombie machines will be easier to identify
and block.
Is Port 25 Blocking a Temporary Thing?
Probably not. As more and more ISPs block Port 25,
spammers will be pushed toward those ISPs who are not
blocking Port 25. This will accelerate the move to Port
25 blocking by all ISPs.
Currently, most DSL and Cable access operators are
either blocking Port 25 or are implementing Port 25
blocking. This includes Cox cable and most Bell System
companies in both the United States and Canada. MSN and
EarthLink also block Port 25 on dialup Internet access
accounts in many areas.
More Information and References
Blocking Port 25 Traffic
'MyDoom' virus reheats the discussion
http://www.broadbandreports.com/shownews/38004
BellSouth Blocking Port 25
Not clearly informing customers
http://www.broadbandreports.com/shownews/43478
Comcast takes hard line against spam
(An article about Port 25 Blocking).
http://news.zdnet.com/2100-3513_22-5230615.html
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