RV082; disable the "DNS Proxy" ability?

Discussion in 'Cisco Small Business Routers and VPN Solutions' started by 0x0A0B0C0D, Jul 1, 2009.

  1. 0x0A0B0C0D

    0x0A0B0C0D Addicted to LI Member


    I'm trying to troubleshoot a problem with an SBS 2008 machine that is behind a RV082. The Microsoft technician that I've been working with has recommended that I try and turn off the "DNS Proxy" capabilities of the network's router. It's a possibility that the router is interfering with the SBS machine's own DNS resolution. I've got a few questions for you all:
    1. What exactly does the term "DNS Proxy" mean? I've been working in IT for a relatively few years and have never come across that term. I've done some Googling and it seems like just a fancy term to describe a standard DNS forwarder. Meaning, the RV082 will service client DNS requests by using the DNS servers that you enter into the Setup > Network page.
    2. Can the DNS Proxy abilities of the RV082 be turned off? Upon searching the web for information, I see the "DNS Proxy" feature listed as one of the benefits of the RV082, but the manual itself doesn't mention anything with that term.
    3. Has anyone ever put zeros in the DNS Server options on the Setup >> Network page? Supposedly a tleast one DNS server is required, but you can save the page with all zeros for DNS servers and then DNS resolution fails. I'm wondering if that's how you turn off the DNS Proxy ability.
    4. Does anyone here administer SBS 2008 behind a RV082?

    Thanks for your help! :biggrin:
  2. d__l

    d__l Network Guru Member

    A device behind the RV082 doesn't have to use the RV082's DNS Proxy. It only does so if you enter the RV082's IP as its DNS server. If you hard code a different DNS server(s), one on the internet, into the device's settings, it will (should) ignore the RV082's DNS Proxy.
  3. 0x0A0B0C0D

    0x0A0B0C0D Addicted to LI Member

    I've done some researching and it seems that the term "DNS Proxy" is just a fancy term (possibly antiquated) for behaving like a forwarder. True that you don't have to use the LinkSys as your forwarder (DNS Proxy), however the suspicion is that the LinkSys (or some network device) is tampering/intercepting the DNS requests of the SBS 2008 machine that is behind the firewall. No other machine has issues with resolving DNS either through forwarders or the LinlSys itself. I suspect that Server 2008's new TCP/IP stack might do something different with the UDP packets that is disliked by one of the network devices between the server and the interwebs. Just about everything that can be done to the SBS machine (including disabling offloading on the server's network card and messing about with MTU sizes) has been done.

    Things I have yet to try:
    • Change out the DSL modem that the network uses. (It's flakey anyway)
    • Update the RV082 firmware from 1.3.6 to 1.3.8
    • Create a Server 2003 DNS server on the network to see if the older stack has issues
    • replace the RV082 alltogether (I'm looking at a SonicWall TZ 180 W)
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