Email falling into the blackhole

[darthbrooks]

At work I've been required to configure some dns blackhole forward lookup zones to keep users from accessing certain websites. They are not supposed to be able to access mail.yahoo.com via a url but they are supposed to be able to send email to @yahoo.com from their company email addresses. After adding the standard forward lookup zone for mail.yahoo.com and configuring it to resolve to 0.0.0.0 I started to notice that my queues started filling up with outbound @yahoo.com emails (future undeliverables).

http://Www.yahoo.com

still resolves on the network (it's supposed to). Why is the blackhole for mail.yahoo.com affecting the delivery of mail for @yahoo.com and how can I fix it?


Thanks,
Darth

 

[netometer]

Hi!
The “Yahoo” mail servers according to the MX records for the domain “yahoo.com” are:
mx1.mail.yahoo.com
mx2.mail.yahoo.com
mx3.mail.yahoo.com
mx4.mail.yahoo.com
mx5.mail.yahoo.com
They are all in the domain mail.yahoo.com. If you have a forward lookup zone for this domain and your Exchange server uses that DNS server for name resolution you will not be able to send emails to e-mail accounts in Yahoo.
There are two solutions that come to my mind – a good and a bad one.
The bad solution is to put the entries above with the corresponding IP addresses in the host file of your exchange server. It is bad because Yahoo might change some of the IP addresses and you will start having the same problem.
The good one is to configure and use different DNS Server(s) for the users and for Exchange. The users’ DNS servers will have the “mail.yahoo.com” zone and the DNS servers for Exchange will not. A lazy way to do this if you don’t have or do not plan to have Active Directory is to use an external DNS server (your ISP DNS servers for example) for the Exchange.

NetoMeter

http://www.netometer.net

 

[darthbrooks]

Thanks, that's exactly the info that I needed. Problem solved.

Thanks again,
Darth

 

[dennisbbb]

Or simply put mail.yahoo.com on the surf-control web filter server, preventing users from openning such page from their browser.