The ARPAnet comes to a complete halt when the first computer virus is accidently propagated around the net. The virus was an email virus affecting the message status of the infected computer. 

ARPAnet splits in two, becoming ARPAnet and MILnet. The number of hosts breaks 1000 globaly and Domian Name System (DNS) introduced. With DNS users do not have to remember the numeric IP address of a computer on the net but can use words to identify a computer. 

The Internet Worm computer virus is released affecting 6,000 computers on the net. The number of total hosts on the net reaches 10,000 later that year.