RV082 and DNS meltdown

Discussion in 'Cisco Small Business Routers and VPN Solutions' started by chrisgbs, Mar 29, 2011.

  1. chrisgbs

    chrisgbs Networkin' Nut Member

    I just started at this organization that has what I believe to be hardware Rev 1 Linksys RV082 set up as Load Balancing with Dual WAN.

    Just recently, people will all at once be unable to access the internet. Pages hang when attempting to load. I've found that pinging an IP address is successful, leading me to believe it's a DNS problem.

    The person who originally set it up used OpenDNS for the DNS servers for both WAN connections. Under DHCP Serving settings, the DNS Server was set to itself, the internal LAN IP. The secondary was set to

    One day when there were several "internet outages," sometimes a power cycle of the router might work, sometimes it would suddenly come back on its own without me doing anything. both internet connections worked properly when I connected them directly to a computer to test. After each outage, many of the computers that were on the network I need to flush their DNS cache for people to be abel to go to google.com or gmail.com or use their mail client to access imap.gmail.com. Many other sites DO work, though.

    In the last instance, I set up the DHCP DNS Servers to OpenDNS and suddenly, everything was working. So, I was happy that I thought I'd resolved the issue as my theory was that the router was being overloaded with DNS translating.

    But, now, it appears that it broke my DNS Local Database. It seems that the DNS Local Database is not looked at if you put custom DNS servers in DHCP hosting preferences.

    My conundrum is

    A. How do I maintain DNS Local Database while putting in custom DNS Servers.

    B. Why when I put the IP of the router's LAN IP (I believe this is the default) as the DNS server, that the router intermittently but frequently dies. (One strange pattern I think I've noticed is that the internet goes "down" when I arrive. Maybe a minute or two after I've woken up my MacBook, I can get internet for a bit, then suddenly everyone goes down. This happens, SOME of the time. I'm doing a clean erase then install on it today to remove it as a factor.)

    Can anyone shed their experience with and possible DNS query problems? Is this even a DNS issue at all?
  2. ylwjeep

    ylwjeep Networkin' Nut Member

    Macs and DNS caching

    Are all of the computers in your office Mac's? There seems to be a nasty new issue that Apple has introduced into Snow leopard with some of the updates they have released, more specifically, ones that have activated DNS caching. Seems like the Cisco RV series routers are having serious issues with how the Apple OS is handling the DNS caching. We've been battling the issue as well, and have yet to find a fix. Apple, as usual, chooses to ignore the issue they have created.
  3. vpnuser

    vpnuser LI Guru Member

    If you have only one custom DNS Server in the LAN of RV082, perhaps you can try specifying RV082's LAN IP as the 2nd custom DNS Server.
  4. chrisgbs

    chrisgbs Networkin' Nut Member

    When directing the RV082 as the DNS server (putting it's own IP address in the DHCP settings,) the internet is slowed down to a crawl. If I put in OpenDNS servers, things are snappy. But, I lose the local DNS database.

    On the Macs, I've tried turning off IPV6 as I've read that has lead to a slowdown in many cases. But, there is always a noticeable improvement to loading web pages when not using the RV082 as the DNS server. I've cleared all settings from the RV082 and the issue persists.

    My solution now is to replace it. I'm not able to upgrade to the latest firmware (I've a hardware version 1 or 2 RV082, thanks for nothing Linksys/Cisco). I've finally found some (overpriced) solutions for Link Balancing from Barracuda and Peplink. They both have fully qualified DNS servers in them. I find it cheaper and easier to manage than a separate DNS server in the office. Maybe in the future if we grow beyond 75-100 people.

    Linksys/Cisco has dropped the ball on this one, and still continue to shop this model number as a "current" product.
  5. Sfor

    Sfor Network Guru Member

    I do not know about RV082, but there is a catch in the RV042 i know about. Both WAN ports have their own DNS servers. But, the router does not pay any attention to what WAN port a particular DNS server belongs. So, it is a common situation to send a DNS requests through a wrong WAN port. It can lead to many unanswered DNS requests.

    One solution is to force the same DNS serwers for both WAN ports, or independent DNS serwers through DHCP settings.

    The other solution is to place routing rules directing DNS requests to proper WAN ports.
  6. Sfor

    Sfor Network Guru Member

    I think I did experience the same symptoms. When one of the DNS servers used by RV082 is not responding the whole DNS service provided by router slows down. It affects the router WEB UI as well.

    The solution is to use proper DNS servers in the WAN setup. So they will always respond to DNS queries from RV082.

    Forcing the DNS servers in DHCP settings will bypass the router DNS server, so the custom DNS service will not work.
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