DNS Forwarder doesn't work with DHCPD Failover



  • Hostnames provided from DHCP clients and registered in the DNS forwarder do not get registered on both systems of a failover pair. I have a CARP LAN interface, adv skew set correctly and the correct settings for Failover Peer IP on both systems.

    The problem is that a DNS lookup of a DHCP hostname only works on one system. Not necessarily the master. This makes DHCP failover unusable for me  :(



  • Agreed, there is a problem syncing hostnames.  I have sacrificed some of the gracefulness of DHCP failover for name resolution consistency by setting the split to be 100% primary 0% secondary fro DHCP.  This cleans up DNS and logs nicely for my site.  Here's my hack.

    on your primary, edit /var/dhcpd/etc/dhcpd.conf
    modify each "split 128" to be "split 255"
    This will cause new DHCP leases to be handed out exclusively from your primary DHCP server in normal state. If primary DHCP fails, requests for leases will go unanswered for a few minutes as the takeover behavior of DHCP is set to take about 10 minutes.  Also, any adjustment or save or the dhcp settings will overwrite/revert this change.

    I have not tested the failover behavior, relying on documentation of dhcpd to be sane.  Hopefully it's accurate, and this option will become a checkbox in the near future.



  • I'm looking for the answer to this problem as well.

    @deadshift

    Keep an eye on this thread to see if we get any answers…

    https://forum.pfsense.org/index.php?topic=69635.msg465570#msg465570

    @neik

    Ill give this a go if I have no luck getting any answers on the forum.

    Thanks,
    Colin



  • I think this is the bug that cmb raised a couple of days ago: https://redmine.pfsense.org/issues/4061
    Seems it is a known issue without a quick fix right now.


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