DNS queries in Windows XP Professional (SP2)

Posted on 2006-03-20
Last Modified: 2013-12-04
My firewall is logging frequent attempts by programs on my computer (such as Lotus Notes, Firefox or the Spooler SubSystem App (c:\windows\system32\spoolsv.exe) to communicate with (seemingly random) servers on the internet on port 53.  They are not attempting to access the DNS servers configured in my network settings.  

Does this mean that I have some sort of infection?  

I have scanned my hard disk with several anti-virus and anti-malware programs and have so far discovered nothing ominous.

Is there a way of discovering whether they are doing genuine dns queries or not?  I had a quick look at Ethereal for example.  Unfortunately with my level of knowledge the output was all greek to me.  (Make that ancient greek mixed up with higher, pure mathematics.)

Question by:twixt
    LVL 15

    Expert Comment

    Are they using TCP or UDP ? Grab the IPs and see if the IP is a legitimate DNS server

    The most likely cause is that your configured DNS server has a forwarder that sends you to another DNS server
    LVL 9

    Expert Comment

    Hi Computron,

    check the ipconfig and network settings for those computers, and see what are the primary and secondary DNS servers over there. make sure that they are your local DNS server.


    Author Comment

    Hi Computron

    I hadn't paid attention to that earlier, I wasn't logging that.  But having a look at the past half an hour or so, it appears they are using UDP.  I'll check further when I am online a bit longer.

    Hi imnajam

    I have looked at the network settings.  The network adaptor has two DNS servers assigned by the ISP.  But these programs are trying to contact servers (I assume) which are not configured.


    Author Comment


    Accepted Solution

    PAQed with points refunded (500)

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