pre-creating reserved leases

Foggi, Nicola NFOGGI at depaul.edu
Fri Feb 27 17:51:03 UTC 2009


while going through the log files i found that during the time the server leased out the new addresses, it was seeing the "peer holds all free leases" problem again, not sure if it's related, but possibly might be.

Started looking through the source code, i can't seem to find anyplace where it looks in the reserved pool during a DHCPDISCOVER, at this point are the reserved leases stored in a separate pool?  (Still digging deeper into the code, but getting way past what I can dive into, so have to bring in some backup to dig deeper).

Nicola

-----Original Message-----
From: Foggi, Nicola
Sent: Fri 2/20/2009 1:34 PM
To: Users of ISC DHCP
Subject: RE: pre-creating reserved leases
 

One would hope, but it appears there might be a bug in which it doesn't honor reserved leases as shown here (note running 3.1.2b1):

-- original lease --
lease 10.100.82.30 {
  starts 3 2009/02/18 23:49:54;
  ends 4 2009/02/19 00:23:38;
  tstp 4 2009/02/19 00:23:38;
  tsfp 4 2009/02/19 00:23:38;
  atsfp 4 2009/02/19 00:23:38;
  cltt 1 2009/02/09 21:21:25;
  binding state free;
  reserved;
  hardware ethernet 00:1a:4b:13:1b:b4;
}

-- logs showing lease not honored --
Feb 18 18:23:40 dhcp-sac-1s dhcpd: DHCPDISCOVER from 00:1a:4b:13:1b:b4 via 10.100.82.1
Feb 18 18:23:41 dhcp-sac-1s dhcpd: DHCPOFFER on 10.100.82.102 to 00:1a:4b:13:1b:b4 (NPI131BB4) via 10.100.82.1
Feb 18 18:23:46 dhcp-sac-1s dhcpd: DHCPDISCOVER from 00:1a:4b:13:1b:b4 (NPI131BB4) via 10.100.82.1
Feb 18 18:23:46 dhcp-sac-1s dhcpd: DHCPOFFER on 10.100.82.102 to 00:1a:4b:13:1b:b4 (NPI131BB4) via 10.100.82.1
Feb 18 18:23:51 dhcp-sac-1s dhcpd: DHCPREQUEST for 10.100.82.102 (10.100.141.242) from 00:1a:4b:13:1b:b4 (NPI131BB4) via 10.100.82.1
Feb 18 18:23:51 dhcp-sac-1s dhcpd: DHCPACK on 10.100.82.102 to 00:1a:4b:13:1b:b4 (NPI131BB4) via 10.100.82.1

oops... that sure didn't work...

-- new lease --
lease 10.100.82.102 {
  starts 5 2009/02/20 19:12:44;
  ends 5 2009/02/20 19:27:44;
  tstp 5 2009/02/20 19:35:14;
  tsfp 5 2009/02/20 19:35:14;
  atsfp 5 2009/02/20 19:35:14;
  cltt 5 2009/02/20 19:12:44;
  binding state active;
  next binding state expired;
  hardware ethernet 00:1a:4b:13:1b:b4;
  client-hostname "NPI131BB4";
}

-- lease after setting reserved (via omapi) --
lease 10.100.82.102 {
  starts 5 2009/02/20 19:20:13;
  ends 5 2009/02/20 19:35:13;
  tstp 5 2009/02/20 19:42:43;
  tsfp 5 2009/02/20 19:42:43;
  cltt 5 2009/02/20 19:20:13;
  binding state expired;
  next binding state free;
  reserved;
  hardware ethernet 00:1a:4b:13:1b:b4;
  client-hostname "NPI131BB4";
}
lease 10.100.82.102 {
  starts 5 2009/02/20 19:20:13;
  ends 5 2009/02/20 19:35:13;
  tstp 5 2009/02/20 19:42:43;
  tsfp 5 2009/02/20 19:42:43;
  cltt 5 2009/02/20 19:20:13;
  binding state expired;
  next binding state free;
  reserved;
  hardware ethernet 00:1a:4b:13:1b:b4;
  set remote-handle = %112;
  client-hostname "NPI131BB4";
}
lease 10.100.82.102 {
  starts 5 2009/02/20 19:20:13;
  ends 5 2009/02/20 19:35:13;
  tstp 5 2009/02/20 19:35:13;
  tsfp 3 2009/01/07 22:51:18;
  atsfp 3 2009/01/07 22:51:18;
  cltt 5 2009/02/20 19:20:13;
  binding state free;
  reserved;
  hardware ethernet 00:1a:4b:13:1b:b4;
  set remote-handle = %112;
}

now in this case it actually did honor it for a period of time, but then just decided to stop... however, i've seen similiar problems when a device initially comes online, so probably something missing someplace in the code, now to attempt to find it..

Nicola

-----Original Message-----
From: dhcp-users-bounces at lists.isc.org on behalf of Elliot Finley
Sent: Thu 2/19/2009 6:05 PM
To: Users of ISC DHCP
Subject: Re: pre-creating reserved leases
 
Foggi, Nicola wrote:
> 
> given the recent discussion around the mac address based leases i'm 
> pretty sure i know the answer, but i was just looking for a way to 
> pre-create reserved leases for hosts, but as i won't have the 
> client-hostname, when they do a discover, it appears it won't match that 
> reserved lease, and instead gives them a dynamic-non reserved lease.
> 
> we're looking to migrate from Cisco Network Registrar (which didn't 
> require the client-hostname to be pre-defined) so just looking for 
> options to make the conversion easier...
> 
> Nicola

Nicola,

If you pre-create your leases and you don't include a uid, then it'll do 
a lookup via MAC.  So it should work.

Elliot
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