Testing
If you just made the changes to DNS it may take 24-72 Hrs
for any cached entries in DNS servers on the Internet to be refreshed. So it
s
best to wait a few days before testing.
- Goto one
of the various web sites that let you test DNS entries, mainly reverse DNS
entries
The example below uses
http://www.webmaster-toolkit.com/ns-lookup.shtml
Another good test site:
http://www.dnsstuff.com/
o
This site also has a single test that will query the various
black\block list servers on the internet. It s good to check the IP address
against these monthly.
- Enter in
the IP address of the server that transmitting mail to the Internet
- Confirm it
resolves to the DNS PTR entries created above
Examples:
- Test the
IP at another site
This example uses:
http://postmaster-us.info.aol.com/tools/rdns.html
- Enter in
the IP address of the server that transmitting mail to the Internet
- Confirm it
resolves to the DNS PTR entries created above
Example:
- Send an
e-mail to another provider, like yahoo.com or an external Exchange system,
to verify the host name is being used correctly
Examples:
From Yahoo.com:
Using Outlook on a different Exchange system:
In the above examples the Received: line is the key line. In
this case the server connecting to mta128.mail.re2.yahoo.com and email.c2.net was
63.227.36.13 and this server said it was mail.altered.com, which is correct.
- You can do
a similar test by following the steps at:
http://postmaster-us.info.aol.com/tools/ipverify.html
Conclusion
Using the steps above you will be able to reduce the chance
of mail being sent from your Exchange server from being blocked or flagged as
spam. Given the millions of spam messages sent per day it in critical that you
do everything possible to prevent your mail from being blocked. Other good
steps are to configure
Sender
ID and to verify that messages are being transmitted from an IP address
that you have correctly configured DNS for.
