% telnet ftp.iij.ad.jp ftp
Trying 2001:240::250:8bff:fe0e:cedb...
telnet: connect to address 2001:240::250:8bff:fe0e:cedb: No route to host
Trying 202.232.2.51...
Connected to ftp.iij.ad.jp.
Escape character is '^]'.
220 ftp0.iij.ad.jp FTP server ready.
USER anonymous
331 Guest login ok, type your name as password.
PASS pass
230 Guest login ok, access restrictions apply.
LIST
425 Can't build data connection: Connection refused.
QUIT
221-
Data traffic for this session was 0 bytes in 0 files.
Total traffic for this session was 293 bytes in 0 transfers.
221 Thank you for using the FTP service on ftp0.iij.ad.jp.
Connection closed by foreign host.