ISC DHCP Failover

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Anybody have any experience with setting up dhcpd in failover mode between two servers? I set this up on a couple of servers, and it seems to be working, but I don’t think it is working “right”. It appears both servers are replying to all requests (which for renewals works okay because they both give the same address, but new requests get two different responses). I thought that only one server would reply to a particular request.

Also, every DHCPACK is followed by a message like this in the log:

Sep 23 15:45:50 rad2 dhcpd: bind update on x.x.x.x from mypeer rejected: incoming update is less critical than outgoing update

Any ideas? I subscribed and asked over on the ISC-operated dhcp-users list but haven’t had any responses. Google finds others asking about the same log message, and the only responses seem to be “well, if you get it for every update, there’s probably some configuration issue” (but nobody ever says what issue might lead to it).

3 thoughts on - ISC DHCP Failover

  • As I understand their fallback that is the design idea — they each hand out diverse ranges…


    Jo Rhett Net Consonance : net philanthropy to improve open source and internet projects.

  • Chris Adams wrote:

    In our /etc/dhcp/dhcpd.conf, we have a stanza

    failover peer “dhcp” {
    primary;
    address ;
    peer port 520;
    max-response-delay 300;
    max-unacked-updates 10;
    mclt 600;
    split 128;
    load balance max seconds 3;
    }

    Hope that helps.

    mark

  • In article <20150923194959.GE2874@cmadams.net>, Chris Adams wrote:

    Well it would probably help if you showed us your dhcpd.conf file from each server.

    But anyway, if it helps, here is what I have working:

    SYSTEM 1 (192.168.100.3)
    ———————-