VirtualBox:~$ lsb_release -crid
Distributor ID:	Ubuntu
Description:	Ubuntu 18.10
Release:	18.10
Codename:	cosmic

VirtualBox:~$ sudo apt install dnet-common
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  dnet-common
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 35.0 kB of archives.
After this operation, 106 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu cosmic/universe amd64 dnet-common all 2.65build1 [35.0 kB]
Fetched 35.0 kB in 0s (95.1 kB/s)
Preconfiguring packages ...
dnet-common: Skipping configure of DECnet
Selecting previously unselected package dnet-common.
(Reading database ... 173328 files and directories currently installed.)
Preparing to unpack .../dnet-common_2.65build1_all.deb ...
Unpacking dnet-common (2.65build1) ...
Processing triggers for systemd (239-7ubuntu10.4) ...
Processing triggers for man-db (2.8.4-2) ...
Setting up dnet-common (2.65build1) ...
dnet-common: Skipping configure of DECnet
usage: update-rc.d [-f] <basename> remove
       update-rc.d [-f] <basename> defaults
       update-rc.d [-f] <basename> defaults-disabled
       update-rc.d <basename> disable|enable [S|2|3|4|5]
		-f: force

The disable|enable API is not stable and might change in the future.
dpkg: error processing package dnet-common (--configure):
 installed dnet-common package post-installation script subprocess returned error exit status 1
Processing triggers for systemd (239-7ubuntu10.4) ...
Errors were encountered while processing:
 dnet-common
E: Sub-process /usr/bin/dpkg returned an error code (1)

VirtualBox:~$ dpkg -l dnet-common
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
iF  dnet-common    2.65build1   all          Base package for Linux DECnet


The same on disco:

VirtualBox:~$ lsb_release -crid
Distributor ID:	Ubuntu
Description:	Ubuntu Disco Dingo (development branch)
Release:	19.04
Codename:	disco

VirtualBox:~$ sudo apt install dnet-common
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  dnet-common
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/35.0 kB of archives.
After this operation, 106 kB of additional disk space will be used.
Preconfiguring packages ...
dnet-common: Skipping configure of DECnet
Selecting previously unselected package dnet-common.
(Reading database ... 138040 files and directories currently installed.)
Preparing to unpack .../dnet-common_2.65build1_all.deb ...
Unpacking dnet-common (2.65build1) ...
Processing triggers for systemd (239-7ubuntu10.4) ...
Processing triggers for man-db (2.8.4-3) ...
Setting up dnet-common (2.65build1) ...
dnet-common: Skipping configure of DECnet
usage: update-rc.d [-f] <basename> remove
       update-rc.d [-f] <basename> defaults
       update-rc.d [-f] <basename> defaults-disabled
       update-rc.d <basename> disable|enable [S|2|3|4|5]
		-f: force

The disable|enable API is not stable and might change in the future.
dpkg: error processing package dnet-common (--configure):
 installed dnet-common package post-installation script subprocess returned error exit status 1
Processing triggers for systemd (239-7ubuntu10.4) ...
Errors were encountered while processing:
 dnet-common
E: Sub-process /usr/bin/dpkg returned an error code (1)

VirtualBox:~$ dpkg -l dnet-common
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
iF  dnet-common    2.65build1   all          Base package for Linux DECnet

VirtualBox:~$ tail /var/lib/dpkg/info/dnet-common.postinst

# Automatically added by dh_installinit/11.2.1ubuntu1
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
	if [ -x "/etc/init.d/decnet" ]; then
		update-rc.d decnet start\ 39\ S\ .\ \ stop\ 11\ 1\ . >/dev/null
		invoke-rc.d decnet start || exit 1
	fi
fi
# End automatically added section