On Mon, 08 Oct 2001, Ulysees wrote:
> have a very strange problem with my tftpd
> on the local machine i can tftp to myself and download a file ok
> when i try to upload a file it doesn't work, it will create a 0 length file
> in the tftproot but nothin more
>> Anybody ever come across this ? seems a bit odd
This is something I was told by a friend at some stage.
Try doing it in passive mode. You may find you're going through a firewall
somewhere. I'm not totally sure of the technical bits, but I've a feeling
it causes the client to be flexible about the port and allow the firewall
to set it or something like that.
As I say, I don't honestly understand in detail, but this sounds like the
problem I had. From the ncftp man page:
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
passive mode only, which you can do from a ncftp command
prompt like this:
set passive yes
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.
Otherwise, if you know you need to have ncftp communicate
directly with a firewall or proxy, you can try editing the
separate $HOME/.ncftp/firewall configuration file. This
file is created automatically the first time you run the
program, and contains all the information you need to get
the program to work in this setup.
The basics of this process are configuring a firewall
(proxy) host to go through, a user account and password
for authentication on the firewall, and which type of
firewall method to use. You can also setup an exclusion
list, so that ncftp does not use the firewall for hosts on
the local network.
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