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Command Unrecognized... (4 posts)

This is an archived topic. The information in it is likely to be out-of-date and no longer applicable to current versions of Fetch.
  • Started 20 years ago by Sensei
  • Latest reply 20 years ago from Jim Matthews
  • Sensei Member

    While downloading some AIF files from a WebStar server, I encountered a failure, then checked the server log to see what's up. Found something unusual:
    64.170.53.xxx - MyUsername [Tue Nov 25 13:02:01 2003] WebSTAR FTP: Command unrecognized (TR BigHouse.PB02) 1095/8106983

    BigHouse.PB02 is the name of the file I tried to download. Don't know what 'TR' is, but it's not a command I've seen before. So, it looks like Fetch tried to issue the command "TR BigHouse.PB02" which, of course, the server did not recognize. Do you know why this happened, and how I can prevent it from happening again? Thanks for your help

    [This message has been edited by Sensei (edited 11-25-2003).]

    Posted 20 years ago #

  • Jim Matthews Administrator

    This is speculation, but my guess is that Fetch sent the command "RETR BigHouse.PB02" (RETR is the command to retrieve, aka download, a file) and the first two characters were lost, resulting in the invalid "TR" command.

    I've seen commands get truncated in this way as a result of bugs in devices (such as routers) that do Network Address Translation. When they translate the address in the PORT command (which comes before RETR) the new address sometimes is longer than what they started with, and if they don't handle that correctly they can overwrite the next two characters of the following command (i.e. the RE of RETR).

    I would look for a firmware upgrade for your router. Also, I'd try checking the "Use passive mode transfers (PASV)" box in the Firewall section of Fetch Preferences. That way Fetch will use the PASV command rather than PORT, and the translation issue won't come up.

    Thanks,

    Jim Matthews
    Fetch Softworks

    Posted 20 years ago #

  • Sensei Member

    Thanks for your reply, Jim. Regarding the router that may be at fault, are you referring to the router on the SERVER side, or the router at the CLIENT'S place? The one at the server is definitely doing NAT, and the one at the client is assigning IPs using DHCP.

    Posted 20 years ago #

  • Jim Matthews Administrator

    It could be either, but I'd start with the local device. Any device doing NAT has to translate the FTP PORT commands it sees.

    Thanks,

    Jim Matthews
    Fetch Softworks

    Posted 20 years ago #

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