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ftpaixftp-clientftps

AIX 7.1 anonymous ftp fails


I have a "vsftpd" server running on a RHEL machine which is configured for anonymous communication.

I am trying to connect to it from a AIX 7.1 machine using ftp client.

ftp -snv host 8043
Connected to host
220 secure FTP service
ftp> user anonymous mypass
234 Proceed with negotiation.
TLS Auth Entered.

Certificate:
     ....
     ....
TLSv1/SSLv3 ( ECDHE-RSA-AES256-GCM-SHA384 ), 256 bits
331 Please specify the password.
230 Login successful.
200 PBSZ set to 0.
200 PROT now Private.
ftp> passive
Passive mode  on.
ftp> cd /incoming
250 Directory successfully changed.
ftp> quote pwd
257 "/incoming"
ftp> ls -r
227 Entering Passive Mode (XXX,XXX,XXX,XX,XXX,XX).
ftp: connect: Connection timed out
ftp>

As seen above, the cd and quote pwd command seems to work fine. But ls -r and mput commands fail with Connection timed out error.

No real helpful messages on the server logs also.

Please help on debugging and identifying the issue.

PS: The lftp clients from RHEL work fine connecting to the server.


Solution

  • FTP needs to open two connections to work properly. One for control and one for data. Whenever you get "cd works but ls doesn't", the data connection is not getting established.

    Troubleshooting tips:

    • look for any firewalls/NATs along the way
    • try toggling active/passive mode, this opens the data connection from the other side
    • look at what is happening using network debugging tools like tcpdump/wireshark