2 Replies Latest reply on Feb 7, 2009 11:50 AM by mmgm76

    DNS resolution is flooding our network

    mmgm76

      Not sure how this is happening to this magnitude, but after turning up Netflow on our edge routers and MSFC, we appear to be creating thousands of connections on our Firewall as our internal DNS server tries to resolve FQDN's externally.  

      Is there a simple way to turn off DNS resolution for FQDN's in Netflow or NPM?  We're running NPM 9.2 and NTA 9.1 SP3.

      Thanks,

      George

        • Re: DNS resolution is flooding our network
          davidmaltby

          Yes, there is a Thwack thread about this issue.  It is located here:

          Re: Is NetFlow 3.1 Application Passive or Active???

          You might be seeing the new NetBIOS resolution that we are doing in NTA 3.1.  As you see in the other post, at the present, you can't turn off the NetBIOS from within NetFlow.  We'll correct this in a future service pack hopefully, but you can turn all name resolution off if you want.  But there is a workaround... You can open up your network cards "Properties".  Select the TCP/IP protocol, open its properties, hit the "Advanced" button, click the "WINS" tab and there in the "NetBIOS Settings" grouping, click the "Disable NetBIOS over TCP/IP".

          If it is truly the DNS resolution that you want turned off.  It can be done in NTA 3.1, but you'll need to have Tech Support walk you through how to do it.

          Hope this helps,

          David