[tex-live] anon ftp access to TeX Live perforce

[Nelson H. F. Beebe]

It looks like the issue with the perforce repository is that it needs
a regular, rather than passive, ftp connection.  

The difference has to do with which end assigns the communications
port: the FTP protocol has PORT and PASV commands for the two cases.

	wget --passive-ftp ftp://sun.dante.de:6666/Master/texmf/web2c/texmf.cnf
	[hang...]

	wget ftp://sun.dante.de:6666/Master/texmf/web2c/texmf.cnf
	[works...]

	ncftpget ftp://sun.dante.de:6666/Master/texmf/web2c/texmf.cnf
	[hang...]

	ncftpget -F ftp://sun.dante.de:6666/Master/texmf/web2c/texmf.cnf
	[hang...]

	ncftpget -E ftp://sun.dante.de:6666/Master/texmf/web2c/texmf.cnf
	[works...]

wget by default uses regular mode, while ncftpget by default uses
passive mode.

>From "man ncftpget":

>> ...
>>        -E      Use regular (PORT) data connections.
>> 
>>        -F      Use passive (PASV) data connections.  The  default
>>                is  to  use passive, but to fallback to regular if
>>                the passive connection fails or times out.
>> ...

>From "man ncftp":

>> ...
>>        passive
>>               This controls ncftp's  behavior  for  data  connec-
>>               tions,  and  can  be  set to one of on, off, or the
>>               default, optional.  When passive mode is on,  ncftp
>>               uses  the  FTP  command  primitive PASV to have the
>>               client establish data connections  to  the  server.
>>               The default FTP protocol behavior is to use the FTP
>>               command primitive PORT which has the server  estab-
>>               lish  data  connections to the client.  The default
>>               setting for this variable, optional,  allows  ncftp
>>               to choose whichever method it deems necessary.
>> 
>>    ...
>>    FIREWALL AND PROXY CONFIGURATION
>>        You may find that your network administrator has placed  a
>>        firewall  between  your machine and the Internet, and that
>>        you cannot reach external hosts.
>> 
>>        The answer may be as simple as setting ncftp to  use  pas-
>>        sive  mode  only,  which  you  can do from a ncftp command
>>        prompt like this:
>> 
>>             set passive on
>> 
>>        The reason for this is because many firewalls do not allow
>>        incoming  connections  to  the site, but do allow users to
>>        establish outgoing connections.  A passive data connection
>>        is  established  by  the client to the server, whereas the
>>        default is for the server to establish the  connection  to
>>        the client, which firewalls may object to.  Of course, you
>>        now may have  problems  with  sites  whose  primitive  FTP
>>        servers do not support passive mode.
>> ...

>From "man wget":

>> ...
>>        --passive-ftp
>>            Use the passive FTP retrieval scheme, in which the
>>            client initiates the data connection.  This is some-
>>            times required for FTP to work behind firewalls.
>> ...

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- Center for Scientific Computing       FAX: +1 801 581 4148                  -
- University of Utah                    Internet e-mail: beebe at math.utah.edu  -
- Department of Mathematics, 110 LCB        beebe at acm.org  beebe at computer.org -
- 155 S 1400 E RM 233                       beebe at ieee.org                    -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe  -
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