General discussion

Locked

Spam Server

By Shanghai Sam ·
My company runs Exchange 5.5 SP4 and has been blackholed by the ORDB.org. I've been trying everything I can lay my hands on to shut off this Exchange capability without shutting off my users or our clients from email. I have 12 remote offices usinglocal ISP for internet connectivity, some use the ISP's SMTP server, the rest have to use my Exchange server. All user Outlook configs are Internet Email, not Exchange server. I have tried configuring the IMS Connections tab to "Clients can only submit if homed on this server" but then outside clients can't send us email. I'm out of options. Any help would be appreciated.

This conversation is currently closed to new comments.

5 total posts (Page 1 of 1)  
| Thread display: Collapse - | Expand +

All Comments

Collapse -

Spam Server

by Chris Scharff In reply to Spam Server

http://www.exchangeadmin.com/Articles/Index.cfm?ArticleID=7696

Collapse -

Spam Server

by maxwell edison In reply to Spam Server

Configuring Internet Mail Connector To Stop Open Relay

Since all the configuration changes happen in the IMS, the first step is locating the properties for the service. Open your Exchange Administrator program and connect to the Exchange server that has the IMS service installed. You will notice that the Exchange Administrator is set up just like Windows Explorer with Containers on the left hand side and objects on the right hand side. Once open find the Connections container located under your <organization>\<site>\configuration container in the left hand column. Once highlighted you will notice connector objects on the left hand side, one should be named Internet Mail Service (<server name&gt. You can view the IMS properties by double clicking on it. Once open you will see several tabs, locate the Routing tab and click on it to view the routing properties.

The first thing you notice near the top of the properties sheet is the option of Do not reroute incoming mail or Reroute incoming SMTP mail (required for POP3/IMAP4 support). The obvious choice would seem to be the first, but, do not use it for your system will not relay messages, but will receive them and then send a non-deliverable message back to the return address ofthe message. This is not good because first it put undo burden on your email system by accepting potentially very large email messages but could also be used as a reverse UCE attack with your system involved. The best selection here is the second selection.

(continued..)

Collapse -

Spam Server

by maxwell edison In reply to Spam Server

.
.
Next you see a box titled Routing. On the right hand side of the screen select the add button. In the ‘email sent to this domain’ enter your domain name. Next select the option ‘should be accepted as "inbound"’ indicating that these are the only domains that the SMTP server will accept mail for.

After you have set all of the domains that your server will be accepting mail for click on the ‘routing restrictions’ to open your ‘routing restrictions’ properties page. The first option is ‘Hosts and Clients that successfully authenticate’ which allows relaying of messages to only users that have accounts on your server or another way to validate who the user is with the server.The next option is ‘Host and Clients with these IP addresses’. With this option you can specify by IP address who is allowed to relay through your system or what subnet is allowed to relay through your system. For example a single IP address would put in their address and the subnet mask of 255.255.255.255. For a subnet you would specify the network portion of the IP address and let 0 represent the client addresses with the subnet mask to match. The next option is ‘Hosts and Clients connecting to these internal addresses’. What this does is allows relaying of clients who can access a specific interface on a multi-homed system. Do not check this unless you have reason to do so. And the last option you have to preventopen relaying through your Exchange server is ‘Specify the hosts and clients that can NEVER route mail’. This option is pretty self-explanatory and works by denying specific IP address or subnets.

After all the changes have been made to secure your SMTP server you have to stop and restart the Microsoft Exchange Internet Mail Service located in the services on the control panel.

(continued..)

Collapse -

Spam Server

by maxwell edison In reply to Spam Server

.
.
The preceding came from the following Web site. Be sure to check it out, as there is a lot of useful information on the whats and whys of open relay mail servers, much more than I posted here.

http://rr.sans.org/email/open_relay.php

Another useful article is posted on the James Madison University site:

http://www.jmu.edu/computing/emailupgrade/upgrade012601.shtml

(REMOVE SPACES from the pasted URL.)

Best of luck,

Maxwell

Collapse -

Spam Server

by thambi_r In reply to Spam Server

when you set the option that only the people having account in the server can send mail through your server, In the client side (Outlook Express, Outlook), we have to enable the option "server require authentication" and choose as same as pop3 account in that.Then they can send mails through your mail server.

Back to Software Forum
5 total posts (Page 1 of 1)  

Related Discussions

Related Forums