Select Page

The Day The Infant Internet Uttered Its First Words

Author: Professor Leonard Kleinrock | Kleinrock webpage

The following is a record of the first message ever sent over the ARPANET. It took place at 22:30 hours on October 29, 1969. This record is an excerpt from the “IMP Log” that we kept at UCLA. I was supervising the student/programmer Charley Kline (CSK), and we set up a message transmission from the UCLA SDS Sigma 7 Host computer to the SRI SDS 940 Host computer. The transmission itself was simply to “login” to SRI from UCLA. We succeeded in transmitting the “l” and the “o”—but then the system crashed. Hence, the first message on the Internet was “lo”! We were able to do the full login about an hour later.


Below, the page is reproduced with highlights showing the date and the critical entry


The following is a scan of the cover of the UCLA IMP LOG in which the above entry was made: