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# grep -i ftp inetd.conf
ftp     stream  tcp     nowait  root    /usr/sbin/ftpd
# oslevel -s            

So I have an AIX 6 server. How can I check if FXP is enabled on the FTPD or not?

share|improve this question
No, I tried to google for it, but there aren't many articles about that the AIX FTPS supports FXP or not.. – LanceBaynes Jan 17 '12 at 18:34
up vote 3 down vote accepted

According to IBM's AIX documentation for ftpd, there is a -ff flag which:

Disables checking for both a privileged port and an IP address that matches the one used for the control connection when the client requests the server to connect back to a specific client port. Using this flag enables the client to request that the server send data to an alternate host or interface. By default, ftpd does not allow this action as a security precaution.

This seems as though it would allow FXP, especially since according to Wikipedia:

Although FXP is often considered a distinct protocol, it is in fact merely an extension of the FTP protocol and is specified in RFC 959

If that is the case, FXP is disabled by default since the option is not specified in inetd.conf. You can confirm by adding the flag and trying to initiate an FXP transfer. The transfer should only be allowed when the flag is in place.

share|improve this answer
+1 for the search @Justin :-) – Nikhil Mulley Jan 24 '12 at 16:51
oops, I did not notice that my daily vote limit reached, and I typed the comment before even pressing upvote. I will vote in few hours :-) – Nikhil Mulley Jan 24 '12 at 17:53
I just did it :-) – Nikhil Mulley Jan 25 '12 at 5:16
Thanks, @Nikhil. Unfortunately I do not have an AIX box to verify the option - perhaps someone else can confirm. – Justin Ethier Jan 25 '12 at 14:38

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