RE: strange DNS behavior over the last 2 days

From: Levinson, Karl (LevinsonK@STARS-SMI.com)
Date: 03/28/03

  • Next message: Jacob: "Re: strange DNS behavior over the last 2 days"
    From: "Levinson, Karl" <LevinsonK@STARS-SMI.com>
    To: 'steve baker' <stephenbbaker@hotmail.com>, incidents@securityfocus.com
    Date: Fri, 28 Mar 2003 16:00:29 -0500
    
    

    Two thoughts: when I see different results from NSLOOKUP and PING, I think
    about checking other sources of name resolution, such as WINS or NetBIOS
    name broadcast requests [and looking at the local machine name cache using
    NBTSTAT -c and IPCONFIG /FLUSHDNS on Windows 2000 to display, NBTSTAT -R and
    IPCONFIG /FLUSHDNS to flush the local caches]. If the problem is due to
    NetBIOS names, you might consider confirming your firewall blocks NetBIOS
    both to and from the internet.

    Also, you might read the article at www.cert.org concerning DNS cache
    poisoning [Microsoft naturally had to rename it to "pollution"] and see if
    that might apply to your situation. If this was the case, flushing the name
    caches on both the local host and the server [for example by restarting the
    DNS service] would probably make the problem go away immediately [though
    temporarily]. Whether or notn this is the problem here, IMHO you really
    should consider enabling the setting to prevent cache poisoning on probably
    any Microsoft DNS server as described here:

    http://support.microsoft.com/default.aspx?scid=kb;en-us;241352

    -----Original Message-----
    From: steve baker [mailto:stephenbbaker@hotmail.com]
    Sent: Thursday, March 27, 2003 1:07 PM
    To: incidents@securityfocus.com
    Subject: strange DNS behavior over the last 2 days

    For some odd reason, periodically our clients will visit a site, only to
    have a blank page appear as if the site loaded.

    Nslookup resolves the correct IP address, but ping returns 64.251.66.2 for
    every address that has this problem. There are NO hosts files on these
    machines and regardless of which DNS server we point them to, the same
    problem occurs.

    The problem occurs intermittently as well, which makes it even harder to pin

    down. Some sites previously affected will be accessible and new sites not
    affected suddenly have the same problem - but they eventually clear up in
    just about 10 minutes.

    Very strange. Has anyone heard or seen this before on a network running
    windows nt 4 DNS server with nt/2000 clients?

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  • Next message: Jacob: "Re: strange DNS behavior over the last 2 days"

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