DHCP leases file has 200+ instances of the same lease?

Question

I'm not sure what's going on here. I have a CentOS 7 DHCP server, and the leases file is growing at a linear but steady rate - it's re-issuing the same lease to the same MAC over and over again, and adding the new stanza to the file.

This server serves DHCP for a network of roughly 300 systems.

The DHCP config file looks like this:

ddns-update-style interim;

allow booting;
allow bootp;

ignore client-updates;
set vendorclass = option vendor-class-identifier;
one-lease-per-client true;
option pxe-system-type code 93 = unsigned integer 16;
DHCPDARGS="enp130s0f0";

subnet 10.101.24.0 netmask 255.255.252.0 {
     option routers             10.101.24.1;
     option domain-name-servers 10.101.6.62;
     option domain-search "foo.com";
     option subnet-mask         255.255.252.0;
     range dynamic-bootp        10.101.24.31 10.101.27.254;
     default-lease-time         172800;
     max-lease-time             172800;
     next-server                10.101.24.21;
     class "pxeclients" {
          match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
          if option pxe-system-type = 00:02 {
                  filename "ia64/elilo.efi";
          } else if option pxe-system-type = 00:06 {
                  filename "grub/grub-x86.efi";
          } else if option pxe-system-type = 00:07 {
                  filename "grub/grub-x86_64.efi";
          } else {
                  filename "pxelinux.0";
          }
     }
}

Is it normal behavior for dhcpd to reply to a request for a lease from the same MAC over and over and add its stanza to the end of the dhcpd.leases file, again, over and over?

Is there some setting I'm missing?

score 0 · Answer 1 · answered Jul 16 '16 at 15:43

quoting man 5 dhcpd.leases:

The Internet Systems Consortium DHCP Server keeps a persistent database of leases that it has assigned. This database is a free-form ASCII file containing a series of lease declarations. Every time a lease is acquired, renewed or released, its new value is recorded at the end of the lease file. So if more than one declaration appears for a given lease, the last one in the file is the current one.

Normal behaviour, do not worry.

DHCP leases file has 200+ instances of the same lease?

1 Answers1