Linux ip-172-26-7-228 5.4.0-1103-aws #111~18.04.1-Ubuntu SMP Tue May 23 20:04:10 UTC 2023 x86_64
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Modified use of SYST requests
-----------------------------
The legacy mode, be it with 'auto-login' or not, was to
issue immediately a SYST request to the server, expecting
information as to the 8-bit capabilities of the host.
Since some FTP servers still are built to reject such early
requests, until a valid user had been established with the
client side, the old behaviour caused annoying error response.
These could even disturb the use of intermediary proxy servers.
As of package 'ftp_0.17-25' this behaviour has been intention-
ally changed, sending SYST only with auto-login, or when issuing
the commands 'user' and 'system'. A code analysis could uncover
no ill effects of this step. Keep in mind that other FTP client
software continue the legacy mode, such as OpenBSD, while yet
others have removed it, like FreeBSD. Still others issue a SYST
request, but suppress any returned reject message. The client
available as 'inetutils-ftp' shows this latter behaviour.
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