Exchange: Using XBL block list to filter incoming email.

Spam spam spam.. Let's block them using XBL black list.
Exploits Block List (XBL) is a database which has been frequently updated for any known spam mail sender. You can configure your Exchange server on its Connection Filter to use any or multiple XBL lists to filter spam messages.

Open Exchange System Manager,  First Organization, right click Message Delivery, left click on Connection Filter tab.then enter any known XBL FQDN

 

For more information regarding XBL block list, please check out in Wiki:

http://en.wikipedia.org/wiki/The_Spamhaus_Project

Exchange: testing SMTP email function using TELNET

One way to troubleshoot a email server is back to basic: By sending test message through telnet and SMTP alone. No GUI component involve and more meaningful connection message log to look at.  

In this situation, I have a email server emailhost.hostname.com. which its outgoing message had been queue up. I wonder where is the cause of the problem? the email server act up? firewall blocking the outgoing mail? or DNS problem?

From my email address which is admin@hostname.com I am trying to send a test message to sender@hostname.com (assume that sender is a external email address. like hotmail, gmail etc.)

From DOS prompt, type the exchange server host name with the SMTP port 25: (command line input as underline text. )

telnet emailhost.hostname.com 25

220 emailhost.hostname.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 read

y at  Thu, 29 Jan 2009 01:09:30 +0000

ehlo

250-emailhost.hostname.com Hello [219.123.123.11]

250-TURN

250-SIZE

250-ETRN

250-PIPELINING

250-DSN

250-ENHANCEDSTATUSCODES

250-8bitmime

250-BINARYMIME

250-CHUNKING

250-VRFY

250-X-EXPS GSSAPI NTLM LOGIN

250-X-EXPS=LOGIN

250-AUTH GSSAPI NTLM LOGIN

250-AUTH=LOGIN

250-X-LINK2STATE

250-XEXCH50

250 OK

mail from:admin@hostname.com

250 2.1.0 admin@hostname.com....Sender OK

rcpt to:sender@hostname.com

250 2.1.5 sender@hostname.com

data

354 Start mail input; end with <CRLF>.<CRLF>

subject:test email from admin to sender with rDNS ON

now we will see....

.

250 2.6.0 <admin@hostname.com> Queued mail for deliv

ery

If everything goes, the sender will receive a email from admin@hostname.com subject: test email from admin to sender with rDNS ON.. with a body of message as "now we will see."

If the message does not go through it will display additional line of message from the telnet window to tell me where this test message has been stopped.