RSILVERMAN@EAGLE.WESLEYAN.EDU (Richard Silverman) (04/02/89)
Return-path: MAILER-DAEMON@hplabs.HP.COM Received: from hplabs.HP.COM by EAGLE.WESLEYAN.EDU; Fri, 31 Mar 89 11:22 EST Received: from EAGLE.WESLEYAN.EDU by hplabs.HP.COM with TCP ; Fri, 31 Mar 89 05:54:15 PST Date: Fri, 31 Mar 89 05:54:15 PST From: Mail Delivery Subsystem <MAILER-DAEMON@hplabs.HP.COM> Subject: Returned mail: Host unknown To: RSILVERMAN@EAGLE.WESLEYAN.EDU ----- Transcript of session follows ----- 550 hpsecm.tcp... 550 Host unknown 550 <GPH%HPSECM@HPLABS.HP.COM>... Host unknown ----- Unsent message follows ----- Return-Path: <RSILVERMAN@EAGLE.WESLEYAN.EDU> Date: 31-MAR-1989 08:40:05.66 From: Richard Silverman <RSILVERMAN@EAGLE.WESLEYAN.EDU> Subject: ftp To: GPH%HPSECM@HPLABS.HP.COM Paul, >> I am just starting to use ftp, and I have a few questions: >> 1. How does it work? I am currently trying to get into some >> anonymous sites, and am experiencing the following difficulties: >> a: I will be connected to the site, some line noise or something >> knocks me off, and then I can no longer connect to that site. I get >> the following error: >> ftp: connect: No route to host It sounds not like "line noise", but rather that your local gateway goes down or becomes unreachable (could be elsewhere, too, of course). >> b: Some sites I attempt connection to give me the error >> ftp: (site address): Unknown host >> Once I have been bounced off, I seem to get the first message above no >> matter what machine I attempt to open. Is it possible that getting >> bounced screws things up on my machine for some undetermined amount of >> time (say--to the next boot up)? This would make sense, assuming that you were disconnected because the destination became unreachable. >> 2. Is there another method of specifying the address of machine, >> rather than the Arpanet address (i.e., machine.university.edu)? In >> some of the site lists, the give a bunch of numbers with periods >> (302.333.23.2349) that appear to be some kind of address. What is >> this? The basic internetwork delivery protocol is IP (Internet Protocol), which identifies hosts via a 32-bit address. The IP address is generally written as four octets, thus: 129.133.10.10. What you referred to as the "Arpanet address" is a convenience provided by the domain name system, which maps names onto IP addresses. However, you cannot always rely on names, because DNS has to be supported by name servers, which not all sites have. A given name you want to reach may have propagated far enough to be accessible; then again, it may not have. That's why people frequently give the IP address as well. If you're interested, you would find the various RFCs specifying TCP/IP and associated protocols a good place to start for more specifics. Richard Silverman arpa: rsilverman@eagle.wesleyan.edu Computing Center bitnet: rsilverman@wesleyan.bitnet Wesleyan University CIS: [72727,453] Middletown, CT 06457