I updated to 15.04 using the server command sudo do-release-upgrade.
Since the upgrade was complete and after a reboot, I am unable to telnet to the server.
Port 23 is not listened while the telnetd, xinetd are configured and restarted.
I followed instructions on Telnet Server not starting as well as on http://ubuntuguide.net/install-and-enable-telnet-server-in-ubuntu-linux
restarted a few times but telnet is just not there. Connections are refused.
The server has not changed its IP address and it is the same network as before. There are no firewalls blocking access.
I also installed it from fresh (on a VM) and neither telnet or ssh work. Connection refused on ports 22 and 23.
Further to comments below, telnet and ssh do not work from the server itself let alone from PCs on the same network. Before the upgrade the telnet & ssh was operating and after the upgrade, a couple of hours later, it did not. I used a telnet session to login and kick start the upgrade. It is definitely not a firewall issue.
I used the latest ISO image for the VM and the automatic update from the server.