Re: HGFTP - how to troubleshoot data connection

david20_at_alpha1.mdx.ac.uk
Date: 10/11/03 

Date: Sat, 11 Oct 2003 00:10:45 +0000 (UTC)

In article <CKGhb.1732$Pe5.331@edtnps84>, Alder <PGDEHMKOKIMD@spammotel.com> writes:
>Andy Bustamante wrote::
>
>> I would venture that NAT on the outgoing data connection is not preserving
>> port 20. If this is for a home network I'd recommend on of the internet
>> gateways (SMC, Netgear, Linksys, 3Comm . . .). Or you can download a patch
>> for your system from www.redhat.com. I run Linux on an older AMD for my DSL
>> gateway.
>
>I found that clients CAN connect to my HGFTP server, but only if they're
>using Active mode and don't have a firewall on their end. I'd like to
>support Passive mode connections, but I don't see anything in the HGFTP
>docs that would suggest it supports Passive mode. I also checked the
>docs for the FTP server in TCPIP Services for OpenVMS and didn't find
>anything in there either.
>
>Does anyone know if either of these servers DOES support Passive mode
>connections, and how to enable it?
>

Don't need to do anything special to the DEC TPIP services ftp server.
The client just needs to request passive mode.

Alpha2:tcpip show ver

  Compaq TCP/IP Services for OpenVMS Alpha Version V5.3 - ECO 2
  on a AlphaServer 2100 5/300 running OpenVMS V7.3-1

Alpha2:ftp alpha2
220 alpha2.AXP.MDX.AC.UK FTP Server (Version 5.3) Ready.
Connected to alpha2.
Name (alpha2:david20):
331 Username david20 requires a Password
Password:
230 User logged in.
FTP> passive
_ON|OFF|AUTO|ALL: on
Passive is ON.

(you can also use the "VMS syntax"

SET PASSIVE ON

)

HELP in FTP describes the various options

FTP
FTP> help set passive

SET

  PASSIVE

       Controls whether the FTP client or server initiates data
       connections.

       DCL Format

         SET PASSIVE keyword

       UNIX Format

         passive keyword

    Additional information available:

    Parameters Example

SET PASSIVE Subtopic? par

SET

  PASSIVE

    Parameters

      keyword

         The FTP client program starts with the value AUTO. All keyword
         comparisons are done without regard for typographical case (case-
         blind).

         o ALL

            Does nothing.

         o AUTO

            The FTP client uses the version of network protocol in use on
            the control connection to determine how the data connection is
            initiated. If the network protocol is IPv4, FTP client behaves
            as though SET PASSIVE OFF had been specified. If the network
            protocol is IPv6, FTP client behaves as though SET PASSIVE ON
            had been specified.

         o OFF

            The FTP server initiates the data connection.

         o ON

            The FTP client initiates the data connection. This is often
            useful when a network firewall exists on the path between the
            client and the server and prevents the FTP server from making
            outbound connections.

David Webb
VMS and Unix team leader
CCSS
Middlesex University

>Regards,
>
>Alder
>

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