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port fowarding - Exchange 2007 - trying to avoid being blacklisted

I'm a time warner cable residential customer.  I have exchange server 2007 on Hyper-V.  I'm about to open port 25 and start emailing away for test enviroment.  What is the best way to avoid being blacklisted?  I've been blacklisted twice, and I have to end up waiting 2 weeks to get off the blacklist.  Any suggestions/settings I should make on my exchange server?
Avatar of dsnegi_25dec

Create an SPF record :- this will clear that message is coming from autorized domain.

PTR record :- A Reverse DNS entry (FQDN) must exist for the delivering server and hostname should resolve to the  Same IP address. The PTR record helps to identify the source of emails and authenticity of the source server.

Password Strength :- Password strength should be a strong combination of upper and lower case , characters .

Antivirus :- Should be updated .
txt :- for varification of owernership of domain
Avatar of giltjr
Why were you blacklisted to start with?  Did you leave Exchange setup as a open relay?
for example, if your domain is, name of server is  and ip address of email server is

1. Make sure that if you "telnet 25" from Internet, your server advertise like, but not server.mydomain.local
2. Ping from Internet and you should get
3. in Internet ping -a  You should see[] I think it is your problem.
4. Configure SPF record
5. Check for Open Relay.

Use this service for checking your configuration.
Consider using a Smarthost such as Exchange Online Protection.
There could be lots of possibility causing that way. First of all your cable is not commercial cable, that will cause some junk mail gateway block your IP.
or maybe some one in the same subnet with you trying to send some spam cus the subnet be blocked.

I think the best way is to find another mail gateway for you, so you could just make the mail gateway to trust you.(your IP or domain) so you could send or receive mail throught it.
Avatar of jkimzlg


thanks for the help.  I'm registered with  couldn't do a ptr record or an spf.  Within exchange 2007 I'm able to use smarthost and I'm able to send a receive email.  below is a list of  incoming and outgoing mail servers for Time Warner wants you to use.

I used 'outgoing mail server:'
GoDaddy should let  you do a SPF record. Are you not doing external DNS through GoDaddy?  The PTR record would be created by your ISP, who I am assuming is Time Warner.
Avatar of jkimzlg


I've requested that this question be closed as follows:

Accepted answer: 0 points for jkimzlg's comment #a39741057

for the following reason:

configuring 'smarthosts' in Exchange 2007 is the way to go...
Not sure why this is being closed for 0 points. You said you ended up using a Smarthost which was one of the recommended solutions.
3) Accept one or more Expert posts as the answer

The suggestion in ID: 39737369 was the final answer.
Avatar of jkimzlg


I've requested that this question be deleted for the following reason:

experts-exchange is filled with forced accepts, one expert suggested I spend money and use smarthosts from Exchange Online Protection.  that answer was incorrect, I found the answer myself by configuring smart hosts within exchange 2007 for free.
Exchange 2007 can be configured to use a smarthost but is not a smarthost in of itself. Configuring a smarthost is a hop outside of the Exchange messaging system. I was just using Exchange Online Protection as an example of a smarthost you could use. It's paid, but it is also very good. Instead you picked a free smarthost. Either way, you used a smarthost which was recommended.
Avatar of jkimzlg


diggisaur, pls. say something like the following below, or pls. copy and paste what I put below and I will be happy to give you 100% of the points.

Configure a smarthost within exchange 2007 by going to Organization configuration, Hub Transport, Network, Route mail through smart hosts, add in your ISP's smtp mail server (ie...
Avatar of Gareth Gudger
Gareth Gudger
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