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Configuration Question? (2 posts)

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  • Started 11 years ago by DRFoster
  • Latest reply 11 years ago from Jim Matthews
  • DRFoster Member

    I've got Fetch running in active FTP mode. If I specify a non-standard FTP port for my server, this appears to use the non-standard port for ftp-command (in place of port 21.) Is there a way to tell it use a non-standard port for ftp-data (in place of port 20)?

    I'm trying to use Fetch to access several machines behind an Airport configured with NAT. I can port map ports 20 and 21 (public -> private) into any one of my machines and use Fetch to access it successfully. What I'd like to do is port map 2 different ports to each machine (e.g. 20521 public -> 21 private and 20520 public -> 20 private, ...) so I can use Fetch to access any of the machines.

    Any ideas?

    Since I'm using port mapping, the servers belive they are operating on ports 21 and 20. Setting the non-standard port of Fetch to the port mapped to 21 works for the command channel (I can see this in the transcript window.) Is there a way I can tell Fetch to use a non-standard port (instead of 20) for the data channel?

    Posted 11 years ago #

  • Jim Matthews Administrator

    Fetch does not use port 20. When using active FTP (PORT rather than PASV) Fetch picks port numbers randomly. I suspect this is working because the Airport is rewriting the PORT command. But the Airport only knows to rewrite the PORT command if the connection is to port 21 (otherwise it doesn't know that the connection is an FTP connection).

    I can't think of a way to make this work with the control connection on a non-standard port. That's one of the problems with Network Address Translation (NAT) -- by translating IP addresses and port numbers the Airport Base Station can break protocols that pass those addresses in their commands.

    Jim Matthews
    Fetch Softworks

    Posted 11 years ago #

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