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

[David Froble]

Stephen Hoffman wrote:
> 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.

ayep!  It's going through a firewall with a non-standard port accepting 
incoming FTP connections.