Re: educating rDNS violators

From: Derek Schaible (dschaible_at_cssiinc.com)
Date: 08/25/04

  • Next message: Bryan S. Sampsel: "Re: educating rDNS violators" 
    To: security-basics@securityfocus.com
Date: Wed, 25 Aug 2004 07:00:35 -0400

    On Mon, 2004-08-23 at 15:24, JGrimshaw@ASAP.com wrote:
    > I was under the impression that reverse DNS for the Internet was
    > essentially broken, due to several large ISPs not necessarily implementing
    > reverse DNS for their many subnetted customers.

    I have the (mis)fortune of being a customer of a large ISP who resells a
    portion of a class C to us. As with most customers in this situation I
    run my own DNS with no authority over my reverse DNS. But if you call
    your ISP's help line and ask them to correct your reverse DNS entry for
    your mail servers they more than likely will be ecstatic to help you
    out.

    Personally, I can say my spam reduced over 85% by dropping mail that
    doesn't come from a server with correct reverse DNS information. All
    ISP's want to see spam reduced and if your ISP won't assist you in
    correcting your reverse info, I'd be shopping for a new ISP.

    Hope this helps someone out! 

    -- 
Derek Schaible <dschaible@cssiinc.com>
CSSI, Inc.

  • Next message: Bryan S. Sampsel: "Re: educating rDNS violators"

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