Network host status
ARPANET host status report for October 1971, noting new servers.
Westheimer, E., "Network host status", RFC 252, DOI 10.17487/RFC0252, October 1971, <https://www.rfc-editor.org/info/rfc252>.
@misc{rfc252,
series = {Request for Comments},
number = 252,
howpublished = {RFC 252},
publisher = {RFC Editor},
doi = {10.17487/RFC0252},
url = {https://www.rfc-editor.org/info/rfc252},
author = {E. Westheimer},
title = {{Network host status}},
pagetotal = 3,
year = 1971,
month = oct,
} RFC text
Network Working Group E. Wentheimer
Request for Comments: 252 Bolt, Beranek and Newman
Category: F, G.3 8 October 1971
NIC: 7696
The purpose of this RFC is to report on the recent status of most
Network Hosts. During September 27 through September 29 the BBN
prototype Terminal IMP (Network Address 158) was inaccessible due to
hardware debugging. The Network was, therefore, not examined on
these days.
Three Hosts which were not officially able to act as Server's at the
time of RFC #240 are now able to do so. These Hosts are:
NETWORK SITE COMPUTER
ADDRESS
2 SRI (NIC) PDF-10
6 MIT (Multics) H-645
9 HARVARD PDP-10
The Harvard PDP-10, however, has limited core space. They will,
therefore, run the Telnet program only occasionally.
The following two tables summarize the information on the Host status
for September 30 - October 8.
NETWORK SITE COMPUTER DAY, DATE AND TIME (Eastern)
ADDRESS TH F M Tu W Th F
9/30 10/1 10/4 10/5 10/6 10/7 10/8
1100 1753 1200 1600 1100 1300 1530
1 UCLA SIGMA-7 O T D O #D O O
*65 UCLA IBM-360/91 O O D O D O O
2 SRI(NIC) PDP-10 O #D T #T O T #D
66 SRI(AI) PDP-10 D D D D D D D
3 UCSB IBM-360/75 D O O O O O O
4 UTAH PDP-10 D D D D D D D
69 BBN(TENEX) PDP-10 T T O O O D D
6 MIT(Multics)H-645 O O D T D T T
70 MIT(DM) PDP-10 D H D T D T T
8 SDC IBM-360 D D D D D D D
9 HARVARD PDP-10 T D T D D T T
10 LINCOLN IBM-360 H H H H D T D
where
D = Dead (Destination Host either dead or inaccessible [due to
network partitioning or local IMP failure] from the BBN Terminal
IMP.)
R = Refused (Destination Host returned a CLS to the initial RFC.)
T = Timed out (Destination Host did not respond in any way to the
initial RFC, although not dead.)
H = 1/2 Open (Destination Host opened a connection but then
either immediately closed it, or did not respond any further.)
0 = Opened (Destination Host opened a connection and was
accessible to user.)
* The UCLA IMB-360/91 currently has Remote Job Service (NETRJS),
but has not implemented a full server Telnet System. The BBN
Terminal IMP is not equipped to test NETRJS however, we are
assuming that receipt of the UCLA explanatory message indicates
that NETRJS is also functioning.
# These sites advertise that they may not have their system
available # at these times.
NETWORK SITE COMPUTER STATUS or "STATUS or PREDICTIONS"
ADDRESS PREDICTION OBTAINED FROM
1 UCLA SIGMA-7 Server Jon Postel
65 UCLA IBM-360/91 Remote Job
Service now,
Telnet in April Bob Braden
2 SRI(NIC) PDP-10 Server John Melvin
66 SRI(AI) PDP-10 November Len Chaiten
3 UCSB IBM-360/75 Server Jim White
4 UTAH PDP-10 "Soon" Barry Wessler
5 BBN(NCC) DDP-516 Never Alex McKenzie
69 BBN(TENEX) PDP-10 Server Dan Murphy
6 MIT(Multics)H-645 Server Mike Padliosky
70 MIT(DM) PDP-10 Server Bob Bressler
7 RAND IBM 360/65 User only Eric Harslem
71 RAND PDP-10 January Eric Harslem
8 SDC IBM-360/67 "Soon" Bob Long
9 HARVARD PDP-10 Server Bob Sundberg
73 HARVARD PDP-1 User only Bob Sundberg
10 LINCOLN IBM-360 "Soon" Joel Winnet
74 LINCOLN TX2 Uncertain Tom Barkalow
11 STANFORD PDP-10 November Andy Moorer
12 ILLINOIS PDP-11 User only John Cravits
13 CASE PDP-10 December 15 Charles Rose
14 CARNEGIE PDP-10 January Hal VanZoeren
15 PAOLI B6500 Uncertain John Cravits
16 AMES TIP User only
17 MITRE TIP User only
18 BBN(TIP) Prototype TIP User only
[This RFC was put into machine readable form for entry]
[into the online RFC archives by Kelly Tardif, Via Genie 10/1999]
AI ELI5
On this page
§1Introduction
RFC 252 reports on ARPANET host status from September 30 through October 8, 1971. It notes that during September 27-29 the BBN Terminal IMP was offline for hardware debugging and therefore not available to test hosts. Three hosts that were not official servers in RFC 240 had since become able to act as servers: SRI's PDP-10, MIT Multics, and Harvard's PDP-10, though Harvard had limited core memory and would run Telnet only occasionally.
A report from the first week of October showed that a few more computers could now accept visitors, though Harvard's would only accept them once in a while.
§2Daily Test Results and Status Codes
Testing continued with the same methodology from RFC 240. The report includes a table of daily results for hosts from September 30 to October 8. Several status codes indicated host connectivity: O meant open and accessible, D meant dead or unreachable, T meant timed out, H meant half-open, and R meant refused. Some sites advertised unavailable times. The UCLA IBM-360/91 offered only Remote Job Service and did not yet have a full Telnet server.
Each day showed which computers answered and which did not, using the same letter codes as before to show what happened each call.
§3Host Predictions and Server Status
The report includes a table of 15 hosts with their predicted status, obtained from operators at each site. Most were expected to become servers; some remained user-only (the Terminal IMPs). Several hosts showed unstable behavior, such as Lincoln's IBM-360 (frequently half-open or dead) and SDC's IBM-360 (always dead during this period, though the report did not explain why).
Each host's operator said whether their computer would be available as a shared service, and the results showed which promises came true.