I think it comes down to the FTP server software. If I run vsftpd on an RHEL 8 server I have no issues. But FTP is not secure and I prefer not to have it running all the time. I use some free ftp server software from the Mac app store. It works for every Mac I own except for my Macintosh SE running 6.0.8 with BlueSCSIv2 with the DaynaPORT SCSI/Link emulation.
When I attempt to connect I get this error message: "Server response: Can't connect to specified address."
The transcript window shows this:
220 FTP Server ready.
USER ftpuser
331 Username ok, send password.
PASS
230 Login successful.
SYST
215 UNIX Type: L8
PHD
257 "/" is the current directory.
PORT 192, 168, 7,224, 106, 193
425 Can't connect to specified address. ftp_list: -30000
The APP on the Server side lacks good logging verbosity so I used tcpdump, and I see this:
07:25:32.678941 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags , seq 4078416672, win 1336, options [mss 668], length 0
07:25:32.679216 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [S.], seq 2464341375, ack 4078416673, win 65535, options [mss 1460], length 0
07:25:32.727282 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 1, win 1336, length 0
07:25:32.727852 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 1:24, ack 1, win 65535, length 23: FTP: 220 FTP Server ready.
07:25:32.775873 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 24, win 1313, length 0
07:25:32.848906 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [P.], seq 1:15, ack 24, win 1313, length 14: FTP: USER ftpuser
07:25:32.849031 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [.], ack 15, win 65535, length 0
07:25:32.849145 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 24:57, ack 15, win 65535, length 33: FTP: 331 Username ok, send password.
07:25:32.885710 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 57, win 1280, length 0
07:25:33.009819 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [P.], seq 15:29, ack 57, win 1336, length 14: FTP: PASS ftpuser
07:25:33.009998 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [.], ack 29, win 65535, length 0
07:25:33.010232 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 57:80, ack 29, win 65535, length 23: FTP: 230 Login successful.
07:25:33.084852 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 80, win 1313, length 0
07:25:33.261021 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [P.], seq 29:35, ack 80, win 1336, length 6: FTP: SYST
07:25:33.261079 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [.], ack 35, win 65535, length 0
07:25:33.261190 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 80:99, ack 35, win 65535, length 19: FTP: 215 UNIX Type: L8
07:25:33.335380 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 99, win 1317, length 0
07:25:33.435008 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [P.], seq 35:40, ack 99, win 1317, length 5: FTP: PWD
07:25:33.435159 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [.], ack 40, win 65535, length 0
07:25:33.435305 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 99:134, ack 40, win 65535, length 35: FTP: 257 "/" is the current directory.
07:25:33.483871 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 134, win 1301, length 0
07:25:33.684973 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [P.], seq 40:66, ack 134, win 1336, length 26: FTP: PORT 192,168,7,224,7,141
07:25:33.685091 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [.], ack 66, win 65535, length 0
07:25:33.685400 IP (iMac 2017 13.6.1).54942 > (Macintosh SE 6.0.8).xmapi: Flags , seq 634493559, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 3091313653 ecr 0,sackOK,eol], length 0
07:25:33.710961 IP (Macintosh SE 6.0.8).xmapi > (iMac 2017 13.6.1).54942: Flags [R.], seq 0, ack 634493560, win 65535, length 0
07:25:33.711180 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 134:175, ack 66, win 65535, length 41: FTP: 425 Can't connect to specified address.
07:25:33.769738 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [.], ack 175, win 1295, length 0
07:25:37.310695 IP (Macintosh SE 6.0.8).inspect > (iMac 2017 13.6.1).ftp: Flags [P.], seq 66:72, ack 175, win 1336, length 6: FTP: QUIT
07:25:37.310812 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [.], ack 72, win 65535, length 0
07:25:37.310952 IP (iMac 2017 13.6.1).ftp > (Macintosh SE 6.0.8).inspect: Flags [P.], seq 175:189, ack 72, win 65535, length 14: FTP: 221 Goodbye.
Maybe I'll just try vsftpd install from brew.