[Info-vax] FTP (was Re: unalphabetical help)

[Stephen Hoffman]

On 2013-01-05 20:24:46 +0000, David Froble said:

> I've had only one problem with SmarTerm.  It supports an FTP session, 
> with command line or windows and drag and drop.  I've had a problem in 
> one direction with VMS on Alpha, never on VAX.  However, I've also had 
> a problem between 2 Alphas, which gets fixed by "SET PASSIVE" once an 
> FTP connection is established, so, I don't think it's a SmarTerm issue. 
> I've never bothered to study the "passive" thing with FTP, so I don't 
> know what the problem is, nor why setting "passive" fixes it.  I'm 
> guessing it's something to do with whichever side thinks it's in 
> control.  Perhaps improper handshake when the FTP connection is 
> established.

ftp requires a second connection be established either from the client 
to the server or from the server to the client, and many IP networks 
tend to have client-side or server-side firewalls or NAT devices that 
can block one or both of those additional connections.

The ftp stuff predates IP, and the design is incompatible with 
firewalls that don't poke around inside the traffic to sniff that 
second port.

sftp works better.

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