Re: Ideas on solving the file transfer problem

Robert Wessel wrote:

On Thu, 19 Jan 2012 21:22:13 +0000, Rui Maciel <rui.maciel@xxxxxxxxx>

Domestic users tend to control their own firewalls. Would they be
affected by this?


Well, sometimes they do. But doesn't making such a change move this
out of the range of easy solution for the vast majority of users?

But FTP ports are commonly blocked by (residential) ISPs, along with
SMTP and a few others. You can often ask to get them unblocked.

This isn't a problem. Port 21 may be the default port for FTP, but FTP
servers do provide a way to configure. Regarding the client, it's possible
to provide URLs to a FTP resources that specify a non-default port.


DNS wouldn't be a problem, as domain names aren't exactly necessary. NAT
wouldn't be a bigger problem than it already is.


Given the two channel nature of FTP, NAT is a bigger problem than
usual. Most firewalls that support FTP have specific code to deal
with the data connection. PASV mode helps, but isn't usually the
default, and is often disabled on FTP servers.

Firewalls can be configured by the end-user to open the necessary ports. As
a last resort, it is also possible to use ports which are already opened but
attributed to other services.


But even the usual problems caused by NAT are bad enough, as it blocks
all incoming connections by default. And NAT then imposes an extra
step to determine what the externally visible IP address is.

And without some DNS support, the fairly frequent reassignment of IP
addresses, particularly for residential users, makes using IP
addresses a challenge. Remember, this needs to be easy.

I see what you mean. You have a point with regard to the use of an IP
address posing a challenge.

Nonetheless, one of the reasons, if not the main reason, that IP addresses
may pose a challenge to the average user is the lack of familiarity they may
have with them. If people don't use them directly then they may have to
deal with a learning curve.

Yet, this learning curve isn't particularly steep, if the user only needs to
know what's his current IP address. There are multiple ways to do this,
including a quick google check for "my IP address", which is enough to get
the IP address of either our device or our current routing device.

Regarding the reliance on DNS to simplify this, registering a domain name is
a bit more of a challenge than looking up a device's current IP address.


Perhaps Skype would be a good solution (you can send files during a
conversation).

As this would require yet another middlemen, this wouldn't be a valid
option. Using Skype's ports to transfer files, on the other hand, may be of
some use.


Rui Maciel
.

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