DNS problem

Posted on 2004-11-01
Last Modified: 2012-05-05

Hi everybody, I am using Windows 2000 Server with SP4 and Exchange 5.5 Sp4.

 I am using DNS services to send mail outside. i confiugured exchange 5.5 to send mail using DNS, 2 months back, firstly (up to one week) it was very slow but slowly mails were going fast. That means Exchange server (is also DNS server) caches DNS entries for all domains to which it sent mails before. -- by Chris-Dent and Nyaema.

 but the problem is 2 days back i restarted my exchage server, again mail communication to outside became very slow, mails going outside very slowly. that means Cached DNS entires has been flushed.
Can anybody please tell me how to make Cached entires permanant instead creating manual record.
Or else any alternate solution to make my exchange server fast ?

Thanks and Regards
Question by:javeed_ccna
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    by:Chris Dent

    Are you still using Forwarders in the DNS configuration Javeed?

    Author Comment


    Hi Chris,

    Yeah still i am using forwarders, at last i got the solution, there is no problem in DNS configuration.
    I have antivirus McAfee virus scan enterprise 8.0i. There is an option in antivirus to preventing mass mailing worms from sending mail on port 25. this is preventing my mails to go out side.
    I disabled it , now mails are going out.

    Any how thanks allot for you all.
    Could you please tell me whats the difference between 'Forwarders" and 'roothints'.

    thanks and Regards
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    Root Hints

    Asks the Root Servers (,, etc) for the answers to questions it can't answer directly. These are high performance clusters of servers that host the Top Level Domains (.com, .net, .org, etc etc etc) as well as the . zone in some cases.

    The Root Servers are Authoritative only, they don't cache anything at all, but they do know about everything.


    Asks the Servers specified as Forwarders for answers to questions it can't answer directly. A recursive query or a query from the cache. If it's a common query it should give you an answer from the cache of the server you're asking rather than bouncing around trying to find the original records.

    I'd try removing Forwarders completely and see if using Root Hints is faster. It could be that there's just too much load on the servers you're forwarding queries to.

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