[CentOS] vsftpd and active mode connections causes FTP session to hang

I've encountered an odd error state that I haven't been able to resolve
yet.  I have a customer that, for what ever reason, wants to use active
mode occasionally for FTP xfers.  What they have noticed, is that after
you switch to active, and issue a command (they do 'ls', I've done other
things like 'put' and 'get', etc.), the connection hangs.  If you wait a
bit it returns with a "425 Failed to establish connection".  I've tried
this on three hosts so far (all CentOS 5) and they all behave the same,
some of which there is effectively no firewall (all traffic is allowed
from my workstation to the host, and no restrictions on exiting
traffic).

All google searches about this behavour thus far have talked about old
versions of vsftpd or using filesystems such as FAT, which don't apply
in all cases.  Any ideas?


--Tim
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