10 ms·

loopback addresses (2021)

98 points by chha 4y ago

imgabe 4y ago
Coincidentally, I'm reading Where Wizards Stay Up Late about the development of ARPANet and it says: > In designing the IMPs, BBN made it possible to loop the host and modem interfaces of the machine, so they could conduct “loopback” tests. The loopback test, which could be performed remotely, connected an IMP’s output to its input, effectively isolating the IMP from the rest of the network. This generated test traffic through the interface and allowed BBN to check the returning traffic against the outgoing traffic generated by the IMP. So it seems like it was in there from the very beginning. No mention of the 127/8 address specifically though.
- Klaster_1 4y ago
  Great book, read it after a recommendation here. Even though I studied telecoms, the networking origins were still very hazy, knowing how everything started changes the perspective. As a software developer, I can even relate to some aspects of the effort.
- zrail 4y ago
  The IMPs used an internal protocol that IP rode on top of. Like today, lots of networks use Ethernet at the physical layer today.
mikl 4y ago
I guess this is related to the recent kerfuffle about to making (most of) 127/8 publicly routable to stave off the IPv4 shortage a little while longer. We’re just delaying the inevitable. Sooner or later, the band-aid has got to come off. ~4 billion IP addresses are simply not enough for ~8 billion people. So maybe we should just refuse to pile on more hacks and force the ISPs to get off their ass and upgrade their networks.
- Arubis 4y ago
  I hadn't heard about that proposal; do you have a link to discussion/source? It sounds like a Bad Idea and I'm curious for the arguments in favor.
  - placatedmayhem 4y ago
    https://www.ietf.org/archive/id/draft-schoen-intarea-unicast-127-00.html https://www.ietf.org/archive/id/draft-schoen-intarea-unicast...
    - Arubis 4y ago
      Thank you. This is wild.
    - blibble 4y ago
      that seems completely insane that logic has been hard-coded inside every OS and vast amounts of software for 30+ years and to gain less than 0.8%? they'd do better targeting the reserved multicast range
      - justsomehnguy 4y ago
        > inside every OS and vast amounts of software for 30+ years Ha. Ha. Ha. > that logic has been hard-coded inside The thing is what some things are literally hardcoded. I have a whole bunch of network gear circa 2010 in production. It does support IPv6, but for the most part it is extremely rudimentary. What do you want from a box what implements SSH by running a telnet session over a no-auth SSH session? And while I can run the latest Windows/Linux/Whatever on my server gear, the network gear is not that simple to upgrade.
        vlan0 4y ago
        >I have a whole bunch of network gear circa 2010 in production I ran into this 10 years ago. I decided to roll out IPv6 to clients. Router docs said it was supported. Then I watched CPU usage peg because every packet hit the CPU. Turns out it was implemented in software; no ASIC support. Was quite the buzz kill.
vesinisa 4y ago
The best answer in this old thread (Jan 2021, be sure to open the [thread] view) seems to be this: https://elists.isoc.org/pipermail/internet-history/2021-January/006920.html https://elists.isoc.org/pipermail/internet-history/2021-Janu...
- shadowgovt 4y ago
  This, coupled with the previous answer that because the class A 127 had been reserved, it was hard to tell for backwards compatibility reasons what shenanigans had gone on in that whole subnet, seems to explain how we lost a whole class A subnet to the same function.
CodesInChaos 4y ago
What I don't understand is why IPv6 only has a single loopback address, instead of a /8 or /16. This would enable cool things like the OS mapping each subdomain of localhost to a distinct IPv6 address.
- Faaak 4y ago
  You can use ::ffff:0:0/96 or fc00::/7 for that.
- kortex 4y ago
  Is it possible to just use ::ffff:0:0/96 to map them? e.g. ::ffff:7f00:0/104 maps to 127/8
- zinekeller 4y ago
  Everyone suggesting that ::ffff:0:0/96 is a solution should note that not all network stacks are "unified". Windows' stack isn't unified (try accessing http://[::ffff:7f00:1]/ http://[::ffff:7f00:1]/ while having a loopback server and it won't work) and most non-Linux embedded OSes separate the network stack for size reasons (to the chagrin of IPv6 promoters, but most of them are simply trying to fit something into the half-MB EEPROMS like how most IoT devices don't have 5GHz Wifi support).
  - X-Istence 4y ago
    The server would need to bind to that address, and then it should work fine as long as that address is assigned to a loopback interface. That's the same as any system right now. If I bind to 127.0.0.1 I don't automatically get traffic for or listen on 127.0.0.2
    - zinekeller 4y ago
      > The server would need to bind to that address, and then it should work fine as long as that address is assigned to a loopback interface. ... you haven't worked on Linux or Windows networking stacks. On Linux, typing http://[::ffff:7f00:1]/ http://[::ffff:7f00:1]/ when you have a bound server on 127.0.0.1 will automatically connect to 127.0.0.1. Conversely, it's a illegal operation in Windows: you cannot legally bind even with SYSTEM privileges.
gumby 4y ago
Anyone who is convinced that we really could quickly transition to a carbon-free energy future should consider the v4/v6 transition. V6 has conquered big chunks of networking (mobile telephony) but deploying a v6 on the wider, public internet remains pointless.
- disintegore 4y ago
  IPv4 is not an existential threat
  - gumby 4y ago
    Sure, the analogy is not perfect — e.g. AFAIK there are no subsidies for v4 as there are for fossil fuels. As far as existential threats go: everybody thinks locally and acts globally in most, if not all of their actions. And existential threats and mortality are difficult for people to deal with. In fact there’s a whole branch of human activity devoted to that topic (religion). I don’t mean to reduce the significance of the risk (I dropped my other work and now work in climate repair myself) but I think there is are fascinating and instructive lessons to be learned from this example.
    - DonHopkins 4y ago
      The Internet with its AJAX/ReST architecture enabled by JavaScript in the browser lets you "link globally, interact locally"! I just hope the Big AJAX Industry doesn't bribe congress to subsidize Fossil Protocols such as XML and SOAP, just to delay the transition to more environmentally friendly technologies like JSON and ReST. NOTE: This packet is sold by net wait, not by volume. Packed as full as practicable by modern automatic equipment, it was delayed the full net wait indicated. If it does not appear full when opened, it is because contents have been compressed during shipping and handling.
      - gumby 4y ago
        I had never before thought of "think globally, act locally" as a description of the end-to-end principle.
DonHopkins 4y ago
Keith Henson (who happens to be an old friend of John Gilmore, who wrote the internet-history post we're discussing) had to explain a geeky in joke about the 127.0.0.1 local loopback address, public ftp sites, secret copyrighted Scientologist OT religious texts, and a great troll of the usenet alt.religion.scientology group, in a legal deposition, under oath, to Scientology lawyers, while rolling on the floor laughing hysterically. https://en.wikipedia.org/wiki/Keith_Henson#Scientology https://en.wikipedia.org/wiki/Keith_Henson#Scientology http://smokyhole.org/kh/kh.htm http://smokyhole.org/kh/kh.htm http://www.cryonet.org/cgi-bin/dsp.cgi?msg=6289 http://www.cryonet.org/cgi-bin/dsp.cgi?msg=6289 Readers of alt.religion.scientology were astonished to notice a large collection of alleged secret, copyrighted and trade secret protected documents of the church of scientology posted anonymously over the weekend of May 5. An expert source known to Biased Journalism verified the documents as authentic. [snip--to transcript from a deposition of Keith Henson by the "Church" of Scientology. Lieberman is their lawyer.] Lieberman: do you know who Patrick J. Volk is? Henson: to the best of my knowledge I've never heard of this person. Lieberman explains that Volk is apparently communicating from some educational institution in Pittsburgh. Henson still doesn't recognize the name. Lieberman hands Henson a document. From: hkhenson@shell.portal.com (H Keith Henson) Newsgroups: alt.religion.scientology Subject: Re: OT Materials... Date: 6 Apr 1995 19:35:38 GMT Parick J Volk (pjvst+@pitt.edu) wrote: : Screw the courts.... : I have an ftp site for all the OT materials... : ftp:127.0.0.1 /pub/texts/news/alt/religion/scientology : I don't know how long I'll have it up. : P J Volk : (alt.2600 lives! All hail the clams and trolls!) Great stuff! But don't you expect the 'ho to blow a gasket? Henson: (cracks up) this is a great troll. Lieberman: (acidly) you find this amusing? Henson: yes. It's an in joke. Lieberman quotes from the Volk post: "screw the courts" and also says that he has an ftp site for all the OT materials. "Mr. Henson is laughing hysterically about this posting for reasons that I suppose he understands--" Henson offers to explain. Lieberman: What's an ftp site? Henson explains that ftp means file transfer protocol. You can use almost any machine on the Internet to access a file on almost any other machine, that has been placed in an ftp directory, he says with relish. [He goes on at length about how this is done.] Lieberman: Okay. "So when he said 'I have an ftp site for all the OT materials,' he is saying he has all the OT materials on a site which people can access." Was Henson aware of Patrick Volk's ftp site? Does this refresh your recollection? he demands. Henson: well, you see right after the colon, it says ftp:127.0.0.1? Lieberman: yes. Henson: that's a loopback address. Lieberman wants to pursue the question of the site with the OT materials. Was Henson aware of Patrick Volk's ftp site? Henson: (patiently) It's at 127.0.0.1. This is a loop back address. This is a troll. Lieberman: what's a troll? Henson: it comes from the fishing where you troll a bait along in the water and a fish will jump and bite the thing, and the idea of it is that the internet is a very humorous place and it's especially good to troll people who don't have any sense of humor at all, and this is a troll because an ftp site of 127.0.0.1 doesn't go anywhere. It loops right back around into your own machine. Lieberman [not getting it]: So the idea here was to make the church think that this person had an ftp site and to take action against him and, in fact, he didn't have it; is that your point? Henson: Oh, it's really humorous, and I picked up on it and instantly added something to extend the troll. Extending the trolls like this is an art form of the highest order. Lieberman (acidly): I see. So this is part of your art form where you say, "don't you expect the 'ho to blow a gasket?" Henson: yes. Lieberman (starting to lose his temper): so you do remember this posting apparently? Henson (helpfully): I can't remember for certain that I did this one, and certainly I could not swear to any of the material on here being letter perfect on it (but he goes on to say that it is such a good one that he would be happy to take credit for it). Lieberman: You find this whole thing kind of amusing, don't you? Henson: Oh, this is screamingly funny. Lieberman (no more Mr. Nice Guy): You find it amusing to make Helena Kobrin and the church go after you or other people for this sort of thing, whether you have the materials or not; is that right? Henson: It's a great game. Lieberman: It is a great game. You really find it amusing, don't you? Henson: It's an extremely amusing thing. Lieberman: All right. You find it amusing when you receive these letters from Ms. Kobrin, the cease and desist letters? It's part of the game; isn't it? [This goes on for awhile as Lieberman hammers at the point. Henson reiterates that he is amused, and wants to talk about the SP levels.] Lieberman: You find it an amusing part of the game when you receive these cease and desist letters, right? Henson: No, no. It's not amusing, it's a major increment in status. Lieberman: I see. You feel this increases your status, right? On the internet, on a.r.s. Henson: Yes, absolutely. Lieberman: All right. And it's all part of this game, right? Henson: Absolutely. Lieberman: It's all part of the troll, right? Henson (waving exhibit): This is a great troll. I mean, anybody in the computer business instantly would have spotted this, ftp:127. In fact, it even says trolls in here (indicating). In fact, this was cross-posted from -- Lieberman has heard more than enough about trolls: "There is no question pending. You can hold your comments." Lieberman (with an air of getting into the bizarre nature of the situation): why did you think this would cause Ms. Kobrin to blow a gasket? Henson: this wasn't addressed to Helena. He goes on to explain that the message is a loop back. If it worked at all it would be a loopback to your own machine. If you tried it you'd discover it's a troll. The 127 is the loopback address! It's a joke, but the lawyer isn't getting it. [The observer notices that the RTC lawyer has connected "the 'ho" with Ms. Kobrin. Evidently the nickname has made transit to the solid world. Ms. Kobrin is stuck with it for life.]
DonHopkins 4y ago
In the days of NCP, before TCP/IP (aka ipv4), the original ARPANET TIP manual "Users Guide to the Terminal Imp" (originally written in 1971 by William Crowther, one of the authors of Adventure) documents on page 5-4 the procedure for connecting an input and output socket of one TIP to an input and output socket of another TIP, through an unsuspecting host, so you could chat back and forth directly between two TIP dial-ups, without actually logging into the host. https://archive.org/details/bitsavers_bbntipADA0eTerminalIMPAug75_2157363 https://archive.org/details/bitsavers_bbntipADA0eTerminalIMP... It went something like @HOST #, @SEND TO SOCKET #, @RECEIVE FROM SOCKET #, @PROTOCOL BOTH, making sure the sockets were different parity so as not to violate the Anita Bryant clause with homosocketuality: https://news.ycombinator.com/item?id=12422813 https://news.ycombinator.com/item?id=12422813 You could also add the octal device port number of any other TIP user on your same TIP after the @ and before the command, to execute those commands on their session. (See page 5-7, "Setting Another Terminal's Parameters".) BBN wrote such great documentation and would mail copies of it for free to anyone who asked (that's how I got mine), you couldn't even call it security by obscurity!

98 points by chha 4y ago

Coincidentally, I'm reading Where Wizards Stay Up Late about the development of ARPANet and it says: > In designing the IMPs, BBN made it possible to loop the host and modem interfaces of the machine, so they could conduct “loopback” tests. The loopback test, which could be performed remotely, connected an IMP’s output to its input, effectively isolating the IMP from the rest of the network. This generated test traffic through the interface and allowed BBN to check the returning traffic against the outgoing traffic generated by the IMP. So it seems like it was in there from the very beginning. No mention of the 127/8 address specifically though.

Klaster_1 4y ago
Great book, read it after a recommendation here. Even though I studied telecoms, the networking origins were still very hazy, knowing how everything started changes the perspective. As a software developer, I can even relate to some aspects of the effort.
zrail 4y ago
The IMPs used an internal protocol that IP rode on top of. Like today, lots of networks use Ethernet at the physical layer today.

mikl 4y ago

I guess this is related to the recent kerfuffle about to making (most of) 127/8 publicly routable to stave off the IPv4 shortage a little while longer. We’re just delaying the inevitable. Sooner or later, the band-aid has got to come off. ~4 billion IP addresses are simply not enough for ~8 billion people. So maybe we should just refuse to pile on more hacks and force the ISPs to get off their ass and upgrade their networks.

Arubis 4y ago
I hadn't heard about that proposal; do you have a link to discussion/source? It sounds like a Bad Idea and I'm curious for the arguments in favor.
- placatedmayhem 4y ago
  https://www.ietf.org/archive/id/draft-schoen-intarea-unicast-127-00.html https://www.ietf.org/archive/id/draft-schoen-intarea-unicast...
  - Arubis 4y ago
    Thank you. This is wild.
  - blibble 4y ago
    that seems completely insane that logic has been hard-coded inside every OS and vast amounts of software for 30+ years and to gain less than 0.8%? they'd do better targeting the reserved multicast range
    - justsomehnguy 4y ago
      > inside every OS and vast amounts of software for 30+ years Ha. Ha. Ha. > that logic has been hard-coded inside The thing is what some things are literally hardcoded. I have a whole bunch of network gear circa 2010 in production. It does support IPv6, but for the most part it is extremely rudimentary. What do you want from a box what implements SSH by running a telnet session over a no-auth SSH session? And while I can run the latest Windows/Linux/Whatever on my server gear, the network gear is not that simple to upgrade.
      - vlan0 4y ago
        >I have a whole bunch of network gear circa 2010 in production I ran into this 10 years ago. I decided to roll out IPv6 to clients. Router docs said it was supported. Then I watched CPU usage peg because every packet hit the CPU. Turns out it was implemented in software; no ASIC support. Was quite the buzz kill.

vesinisa 4y ago

The best answer in this old thread (Jan 2021, be sure to open the [thread] view) seems to be this: https://elists.isoc.org/pipermail/internet-history/2021-January/006920.html https://elists.isoc.org/pipermail/internet-history/2021-Janu...

shadowgovt 4y ago
This, coupled with the previous answer that because the class A 127 had been reserved, it was hard to tell for backwards compatibility reasons what shenanigans had gone on in that whole subnet, seems to explain how we lost a whole class A subnet to the same function.

CodesInChaos 4y ago

What I don't understand is why IPv6 only has a single loopback address, instead of a /8 or /16. This would enable cool things like the OS mapping each subdomain of localhost to a distinct IPv6 address.

Faaak 4y ago
You can use ::ffff:0:0/96 or fc00::/7 for that.
kortex 4y ago
Is it possible to just use ::ffff:0:0/96 to map them? e.g. ::ffff:7f00:0/104 maps to 127/8
zinekeller 4y ago
Everyone suggesting that ::ffff:0:0/96 is a solution should note that not all network stacks are "unified". Windows' stack isn't unified (try accessing http://[::ffff:7f00:1]/ http://[::ffff:7f00:1]/ while having a loopback server and it won't work) and most non-Linux embedded OSes separate the network stack for size reasons (to the chagrin of IPv6 promoters, but most of them are simply trying to fit something into the half-MB EEPROMS like how most IoT devices don't have 5GHz Wifi support).
- X-Istence 4y ago
  The server would need to bind to that address, and then it should work fine as long as that address is assigned to a loopback interface. That's the same as any system right now. If I bind to 127.0.0.1 I don't automatically get traffic for or listen on 127.0.0.2
  - zinekeller 4y ago
    > The server would need to bind to that address, and then it should work fine as long as that address is assigned to a loopback interface. ... you haven't worked on Linux or Windows networking stacks. On Linux, typing http://[::ffff:7f00:1]/ http://[::ffff:7f00:1]/ when you have a bound server on 127.0.0.1 will automatically connect to 127.0.0.1. Conversely, it's a illegal operation in Windows: you cannot legally bind even with SYSTEM privileges.

gumby 4y ago

Anyone who is convinced that we really could quickly transition to a carbon-free energy future should consider the v4/v6 transition. V6 has conquered big chunks of networking (mobile telephony) but deploying a v6 on the wider, public internet remains pointless.

disintegore 4y ago
IPv4 is not an existential threat
- gumby 4y ago
  Sure, the analogy is not perfect — e.g. AFAIK there are no subsidies for v4 as there are for fossil fuels. As far as existential threats go: everybody thinks locally and acts globally in most, if not all of their actions. And existential threats and mortality are difficult for people to deal with. In fact there’s a whole branch of human activity devoted to that topic (religion). I don’t mean to reduce the significance of the risk (I dropped my other work and now work in climate repair myself) but I think there is are fascinating and instructive lessons to be learned from this example.
  - DonHopkins 4y ago
    The Internet with its AJAX/ReST architecture enabled by JavaScript in the browser lets you "link globally, interact locally"! I just hope the Big AJAX Industry doesn't bribe congress to subsidize Fossil Protocols such as XML and SOAP, just to delay the transition to more environmentally friendly technologies like JSON and ReST. NOTE: This packet is sold by net wait, not by volume. Packed as full as practicable by modern automatic equipment, it was delayed the full net wait indicated. If it does not appear full when opened, it is because contents have been compressed during shipping and handling.
    - gumby 4y ago
      I had never before thought of "think globally, act locally" as a description of the end-to-end principle.

DonHopkins 4y ago

Keith Henson (who happens to be an old friend of John Gilmore, who wrote the internet-history post we're discussing) had to explain a geeky in joke about the 127.0.0.1 local loopback address, public ftp sites, secret copyrighted Scientologist OT religious texts, and a great troll of the usenet alt.religion.scientology group, in a legal deposition, under oath, to Scientology lawyers, while rolling on the floor laughing hysterically. https://en.wikipedia.org/wiki/Keith_Henson#Scientology https://en.wikipedia.org/wiki/Keith_Henson#Scientology http://smokyhole.org/kh/kh.htm http://smokyhole.org/kh/kh.htm http://www.cryonet.org/cgi-bin/dsp.cgi?msg=6289 http://www.cryonet.org/cgi-bin/dsp.cgi?msg=6289 Readers of alt.religion.scientology were astonished to notice a large collection of alleged secret, copyrighted and trade secret protected documents of the church of scientology posted anonymously over the weekend of May 5. An expert source known to Biased Journalism verified the documents as authentic. [snip--to transcript from a deposition of Keith Henson by the "Church" of Scientology. Lieberman is their lawyer.] Lieberman: do you know who Patrick J. Volk is? Henson: to the best of my knowledge I've never heard of this person. Lieberman explains that Volk is apparently communicating from some educational institution in Pittsburgh. Henson still doesn't recognize the name. Lieberman hands Henson a document. From: hkhenson@shell.portal.com (H Keith Henson) Newsgroups: alt.religion.scientology Subject: Re: OT Materials... Date: 6 Apr 1995 19:35:38 GMT Parick J Volk (pjvst+@pitt.edu) wrote: : Screw the courts.... : I have an ftp site for all the OT materials... : ftp:127.0.0.1 /pub/texts/news/alt/religion/scientology : I don't know how long I'll have it up. : P J Volk : (alt.2600 lives! All hail the clams and trolls!) Great stuff! But don't you expect the 'ho to blow a gasket? Henson: (cracks up) this is a great troll. Lieberman: (acidly) you find this amusing? Henson: yes. It's an in joke. Lieberman quotes from the Volk post: "screw the courts" and also says that he has an ftp site for all the OT materials. "Mr. Henson is laughing hysterically about this posting for reasons that I suppose he understands--" Henson offers to explain. Lieberman: What's an ftp site? Henson explains that ftp means file transfer protocol. You can use almost any machine on the Internet to access a file on almost any other machine, that has been placed in an ftp directory, he says with relish. [He goes on at length about how this is done.] Lieberman: Okay. "So when he said 'I have an ftp site for all the OT materials,' he is saying he has all the OT materials on a site which people can access." Was Henson aware of Patrick Volk's ftp site? Does this refresh your recollection? he demands. Henson: well, you see right after the colon, it says ftp:127.0.0.1? Lieberman: yes. Henson: that's a loopback address. Lieberman wants to pursue the question of the site with the OT materials. Was Henson aware of Patrick Volk's ftp site? Henson: (patiently) It's at 127.0.0.1. This is a loop back address. This is a troll. Lieberman: what's a troll? Henson: it comes from the fishing where you troll a bait along in the water and a fish will jump and bite the thing, and the idea of it is that the internet is a very humorous place and it's especially good to troll people who don't have any sense of humor at all, and this is a troll because an ftp site of 127.0.0.1 doesn't go anywhere. It loops right back around into your own machine. Lieberman [not getting it]: So the idea here was to make the church think that this person had an ftp site and to take action against him and, in fact, he didn't have it; is that your point? Henson: Oh, it's really humorous, and I picked up on it and instantly added something to extend the troll. Extending the trolls like this is an art form of the highest order. Lieberman (acidly): I see. So this is part of your art form where you say, "don't you expect the 'ho to blow a gasket?" Henson: yes. Lieberman (starting to lose his temper): so you do remember this posting apparently? Henson (helpfully): I can't remember for certain that I did this one, and certainly I could not swear to any of the material on here being letter perfect on it (but he goes on to say that it is such a good one that he would be happy to take credit for it). Lieberman: You find this whole thing kind of amusing, don't you? Henson: Oh, this is screamingly funny. Lieberman (no more Mr. Nice Guy): You find it amusing to make Helena Kobrin and the church go after you or other people for this sort of thing, whether you have the materials or not; is that right? Henson: It's a great game. Lieberman: It is a great game. You really find it amusing, don't you? Henson: It's an extremely amusing thing. Lieberman: All right. You find it amusing when you receive these letters from Ms. Kobrin, the cease and desist letters? It's part of the game; isn't it? [This goes on for awhile as Lieberman hammers at the point. Henson reiterates that he is amused, and wants to talk about the SP levels.] Lieberman: You find it an amusing part of the game when you receive these cease and desist letters, right? Henson: No, no. It's not amusing, it's a major increment in status. Lieberman: I see. You feel this increases your status, right? On the internet, on a.r.s. Henson: Yes, absolutely. Lieberman: All right. And it's all part of this game, right? Henson: Absolutely. Lieberman: It's all part of the troll, right? Henson (waving exhibit): This is a great troll. I mean, anybody in the computer business instantly would have spotted this, ftp:127. In fact, it even says trolls in here (indicating). In fact, this was cross-posted from -- Lieberman has heard more than enough about trolls: "There is no question pending. You can hold your comments." Lieberman (with an air of getting into the bizarre nature of the situation): why did you think this would cause Ms. Kobrin to blow a gasket? Henson: this wasn't addressed to Helena. He goes on to explain that the message is a loop back. If it worked at all it would be a loopback to your own machine. If you tried it you'd discover it's a troll. The 127 is the loopback address! It's a joke, but the lawyer isn't getting it. [The observer notices that the RTC lawyer has connected "the 'ho" with Ms. Kobrin. Evidently the nickname has made transit to the solid world. Ms. Kobrin is stuck with it for life.]

DonHopkins 4y ago

In the days of NCP, before TCP/IP (aka ipv4), the original ARPANET TIP manual "Users Guide to the Terminal Imp" (originally written in 1971 by William Crowther, one of the authors of Adventure) documents on page 5-4 the procedure for connecting an input and output socket of one TIP to an input and output socket of another TIP, through an unsuspecting host, so you could chat back and forth directly between two TIP dial-ups, without actually logging into the host. https://archive.org/details/bitsavers_bbntipADA0eTerminalIMPAug75_2157363 https://archive.org/details/bitsavers_bbntipADA0eTerminalIMP... It went something like @HOST #, @SEND TO SOCKET #, @RECEIVE FROM SOCKET #, @PROTOCOL BOTH, making sure the sockets were different parity so as not to violate the Anita Bryant clause with homosocketuality: https://news.ycombinator.com/item?id=12422813 https://news.ycombinator.com/item?id=12422813 You could also add the octal device port number of any other TIP user on your same TIP after the @ and before the command, to execute those commands on their session. (See page 5-7, "Setting Another Terminal's Parameters".) BBN wrote such great documentation and would mail copies of it for free to anyone who asked (that's how I got mine), you couldn't even call it security by obscurity!