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The strange way FTP manages connections goes back to FTP being older than TCP/IP itself, and thus using older circuit-switched networks. It wouldn't have been
by chuckadams 2mo ago
The strange way FTP manages connections goes back to FTP being older than TCP/IP itself, and thus using older circuit-switched networks. It wouldn't have been unusual for a server to dial up the receiving machine on-demand, which didn't have to be the machine running the command session. Before SMTP came around, email was commonly implemented on top of FTP.
- inigyou 2mo agoFTP was written for an early version of TCP/IP (which wasn't called that). Maybe you're thinking of UUCP, which did often run over dial-up circuits and was used for email, but didn't require two connections.
- chuckadams 2mo agoNo, I was thinking of FTP, but I was probably off the mark anyway: I'd noticed that FTP was mentioned in the RFCs and surrounding discussions long before RFC 793, and that it seemed to be behaving like a point-to-point network, but it hadn't occurred to me that it might have just been using an ancestor of TCP/IP -- some variant of the "Host protocol" perhaps? Hard to get the full context, it was before my time: my beard may be grey now, but I'm not that old.
- inigyou 2mo agoThe original version of TCP/IP was (is currently thought to have been) called Network Control Program/Protocol or NCP. There's a reason current legacy IP is version number 4.