RV042 v3 - problems with DHCP on WAN ports

Discussion in 'Cisco Small Business Routers and VPN Solutions' started by Sfor, Mar 14, 2012.

  1. Sfor

    Sfor Network Guru Member

    Last week the ISP introduced a new policy. The traffic leaving the ISP network gets blocked, if there is no active DHCP lease for the sender IP. As the result, the RV042 v3 in my care loses Internet connection every few hours. In the same time the traffic inside the ISP network works perfectly fine. The DHCP leases should be renegociated every 20 minutes. It seems the RV042 stops doing so at some point. The system log does not hold the DHCP negotiation entries, as it did in v1 series, so I can not tell, where exactly the problem is. In any case, there seems to be something wrong with DHCP in the v4.1.1.01-sp firmware.
  2. Sfor

    Sfor Network Guru Member

    After turning on the Network Service Detection function with ISP Host switch active the router brings up just one WAN port after a reboot. Eventualy, the other WAN port starts working after some time, but it does not seem to be sure. Since the When Fail: action was set to Generate the Error Condition in the System Log it should not bring any WAN port down. When the Network Service Detection is turned off, both WAN ports are bringed up after every reboot, always.

    So, it seems, there is yet another bug present, but I'm not entirely sure if it is unrelated to the DHCP issue.
  3. Sfor

    Sfor Network Guru Member

    Well, it looks like, the DHCP problem is not limited to just the RV042 v3 device. It seems an Ovislink IP-1000R does not work reliably with the same ISP. On the other hand RV v1 series routers are working perfectly.

    By my understanding the ISP keeps a country wide central client authorisation database linked to the DHCP services. This was a cause of a recent country wide fault in internet related services from this provider. The other side effect of this system seems to be a significant delay in DHCP server responses. This could be the key factor to the RV042 v3 WAN DHCP related problems.

    I came with idea to set the WAN to static IP, and then get the ISP gateway authorisation with some other router. There are several problems involved, however. The additional router has to have the sam MAC, as the main one. So, there could be some issues with ethernet switch, and a need to use hub, instead.

    In any case, the idea seems to be working correctly with two RV082 v1 routers. Both of them have the same MAC on WAN1 port. The one with static IP does all the work with VPN and network traffic. The other one with DHCP enabled, has all other functions disabled and does nothing except keeping the DHCP lease active. Both of them are connected to the ISP ethernet through a ethernet switch.

    It would be a good idea to find a cost effective device for the DHCP client task. So far the Ovislink IP-1000R proved to be a bad choice, as it does not renew DHCP lease at times (it happened with ethernet hub as well).
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