Expiring leases

Lowrie, Paul paul.lowrie at nz.unisys.com
Mon Mar 24 23:37:34 UTC 2008

Hi Damian,
Yes - Ive had this problem (and still working on a solution). it goes
like this.
Two servers in failover pair and a  PC with PXEboot still enabled.
   PXEboot request from PC is given address "ABCD" by "Server-1"
   Server-1 puts PC=ABCD and ABCD=PC into DNS
   PC keeps booting....
   OS Boot request from PC is given "EFGH"  by "Server-2"
   DHCP has "one_lease_per_client on;"...
   Server 2 tells  Server-1 that  PC now= EFGH,   so
   Server-1 removes the entries given for "PC=ABCD" and :"ABCD=PC" from
the DNS.
    End result - PC has a valid lease and there is nothing in the DNS -
Crux is that this isnt considered a fault as according to "the
specficiations" and other dialogue in this mail list this is a design
    The OS-boot boot packet is sent with a client-identifier
    The PXEboot packet is sent without this identifier,
Therefore "according to the specification" these are different NIC's so
should be given different leases
Cheers  & Good Luck


Setup: two peered servers.

Problem: occasional lost of dns data due to lease expiration.
Looks like workstation omits T1 and T2 communication, and renews its
lease at T3. Well, one peer adds dns data. The other find the lease
expired and removes dns data a split second after the lease was granted.

Anybody with similar problem? Any help would be appreciated!

Log snips:
Mar  3 08:28:57 s_sys at tlpgbrdns-2.edj.ad.edwardjones.com dhcpd: Added
new forward map from USU41602D1.b22838.branches.edwardjones.com to

Mar  3 08:28:57 s_sys at nlpgbrdns-1.edj.ad.edwardjones.com dhcpd: if
USU41602D1.b22838.branches.edwardjones.com IN TXT
"312e461c3d4bf095111c87d30e4f30e7f2" rrset exists and
USU41602D1.b22838.branches.edwardjones.com IN A rrset
exists delete USU41602D1.b22838.branches.edwardjones.com IN A success.

Damjan Stulic
IS Security Identity Management
Edward Jones

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