Apologies if this report turns out to be a duplicate; I did look through
bugs.d.o (and those PRs listed by reportbug) but didn't find an existing
one for this issue.

The problem is that the isc-dhcp-server package installation fails in
it's last step:

  (#) root@master:~
  >>> apt-get install isc-dhcp-server -y
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  Suggested packages:
    policykit-1 isc-dhcp-server-ldap
  The following NEW packages will be installed:
    isc-dhcp-server
  0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
  Need to get 0 B/548 kB of archives.
  After this operation, 1,468 kB of additional disk space will be used.
  Preconfiguring packages ...
  Selecting previously unselected package isc-dhcp-server.
  (Reading database ... 56261 files and directories currently installed.)
  Preparing to unpack .../isc-dhcp-server_4.4.1-2_amd64.deb ...
  Unpacking isc-dhcp-server (4.4.1-2) ...
  Processing triggers for systemd (240-2) ...
  Processing triggers for man-db (2.8.4-3) ...
  Setting up isc-dhcp-server (4.4.1-2) ...
  Generating /etc/default/isc-dhcp-server...
  restorecon: lstat(/var/lib/dhcp/dhcpd.leases) failed: No such file or directory
  dpkg: error processing package isc-dhcp-server (--configure):
   installed isc-dhcp-server package post-installation script subprocess returned error exit status 255
  Processing triggers for systemd (240-2) ...
  Errors were encountered while processing:
   isc-dhcp-server
  needrestart is being skipped since dpkg has failed
  E: Sub-process /usr/bin/dpkg returned an error code (1)
  Disabling copy-on-write on /var/cache/apt/pkgcache.bin

This is easily fixed with "touch /var/lib/dhcp/dhcpd.leases" followed by a
reinvokation of apt-get:

  (#) root@master:~
  >>> touch /var/lib/dhcp/dhcpd.leases; apt-get install isc-dhcp-server
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  isc-dhcp-server is already the newest version (4.4.1-2).
  0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
  1 not fully installed or removed.
  After this operation, 0 B of additional disk space will be used.
  Do you want to continue? [Y/n] y
  Setting up isc-dhcp-server (4.4.1-2) ...
  Job for isc-dhcp-server.service failed because the control process exited with error code.
  See "systemctl status isc-dhcp-server.service" and "journalctl -xe" for details.
  invoke-rc.d: initscript isc-dhcp-server, action "start" failed.
  [...expected service startup errors regarding lack of configuration...]

Yes using touch to create the file looks like the correct solution to this
problem.  Probably should unconditionally create the file with touch as
there's no reason not to have it.  Maybe use install so you can easily set the
correct permissions on the file.

Also you need to do the same thing for /var/lib/dhcp/dhcpd6.leases

Dear submitter,

as the package isc-dhcp has just been removed from the Debian archive
unstable we hereby close the associated bug reports.  We are sorry
that we couldn't deal with your issue properly.

For details on the removal, please see https://bugs.debian.org/1143544

The version of this package that was in Debian prior to this removal
can still be found using https://snapshot.debian.org/.

Please note that the changes have been done on the master archive and
will not propagate to any mirrors until the next dinstall run at the
earliest.

This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
ftpmaster@ftp-master.debian.org.

Debian distribution maintenance software
pp.
Thorsten Alteholz (the ftpmaster behind the curtain)