[techtalk] ftp_masq stopped working...?

Laurel Fan lf25+ at andrew.cmu.edu
Tue Apr 18 21:57:01 EST 2000


Sent a reply to the original message, but apparently it didn't get there,
so here it is:

Excerpts from mail: 8-Apr-100 Re: [techtalk] ftp_masq sto.. by Walt at fred.net 
> well, I'm not completely sure how to tell,
> but if I insmod ip_masq_ftp, it tells me 
> it's already existing.
 
The command to list modules is 'lsmod' (and incidentally, the command to
remove modules is rmmod.  sometimes unloading and reloading a module
helps).  It does looks like it's still there.
  
> I haven't rebooted in 21 days (yeah yeah, I know
> this isn't windows, but might that help if I did?
> I'm still getting used to the concept of 'stability')
>  
> and no, btw, it behaves identically in passive or
> active mode, just barely gets a few K uploaded and
> then bogs down and stops.
 
If passive mode doesn't work, then it's probably not a problem with
ip_masq_ftp module.  Detailed explanation below, if you're interested.
 
It could be a problem with the server, net connection from the masqer
to the outside, ipmasq, or the windows box.
 
To see which it is, you could:
[upload|download] from [the masqer|the windows box|another machine
behind ipmasq (if you have one)] to [the server|somewhere else] with
[ftp|something else].  Finding out which of these work and which don't
could give you clues about what's breaking and how.
 
It could just be some strange transient bug that'll mysteriously never
happen again if you reboot... I know it's a windows-y answer, but if
you don't feel like debugging, you could try that first.
 
btw, what kernel are you using?  The ipmasq in 2.0.x kernels is a bit
less stable than in 2.2.x kernels.
 
The reason why you need a special module for active/port ftp is that 
in this case, a separate connection is opened from the server to the
client (the PORT request).  When doing ipmasq, the connection is between
the server and the ipmasqer, rather than the actual client.  The special
module is needed so the ipmasqer knows to forward the connection from
the server to the client.






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