Are you sure you're not thinking about CPT? I heard IBM came and asked about just buying CPT and we figured that if they want it, it must be pretty good, so we said no.
Gary
-----Original Message-----
From: IBM TCP/IP List [mailto:IBMTCP-***@VM.MARIST.EDU]
Sent: Monday, March 20, 2006 12:00 PM
To: IBMTCP-***@VM.MARIST.EDU
Subject: Re: [IBMTCP-L] FTP passive mode?
Steven, you got it backwards, IBM approached Interlink with that
request.
The (ex)pres. turned them down !!!!
Fred
-----Original Message-----
From: IBM TCP/IP List [mailto:IBMTCP-***@VM.MARIST.EDU] On Behalf Of
Steven St.Jean
Sent: Thursday, March 16, 2006 1:20 PM
To: IBMTCP-***@VM.MARIST.EDU
Subject: Re: FTP passive mode?
Charles,
[TCPaccess] was a good product - only about two or three times as fast
as the competition.
At one time, that was true. The president of Interlink once approached
IBM with a serious proposal that they should give up trying to develop
an IP protocol stack over MVS, and instead resell ours.
They didn't take him up on it. Instead, they went to work and improved
their own product's performance by several orders of magnitude.
I like to think we had something to do with that.
Steven
-----Original Message-----
Charles Mills
Sent: Thursday, March 16, 2006 12:32 PM
Subject: Re: FTP passive mode?
Oh, I hear you. Toggles are ALWAYS a DISASTER for the sort of reasons
you allude to. What's a script supposed to do?
I didn't mean in some narrow sense "I think the CS client should send
a PASV command by default." I meant in a larger sense "I don't
understand what the negative would be if all FTP ran passive."
Good to hear from you. We were Interlink partners at my old company.
It was a good product - only about two or three times as fast as the
competition.
Charles
-----Original Message-----
Steven St.Jean
Sent: Thursday, March 16, 2006 9:16 AM
Subject: Re: FTP passive mode?
Charles,
Post by Charles MillsFrankly, in my medium amount of FTP experience, I don't
know why it's
Post by Charles Millsnot the default. Doesn't seem to hurt anything.
This was also the recommendation of RFC 1579, "Firewall-Friendly FTP"
.
When we implemented it in the TCPaccess FTP client at Interlink, we
did just that and made it the default behavior.
It was a nightmare.
The whole thing depends on FTP servers supporting the PASV command.
RFC
1579 blithely assumes that non-conforming servers "will return a '500
Command not understood' message; it is a simple matter to fall back to
current behavior." If only it were so simple!
After we'd made the change, we (or rather, our customers) discovered
servers who only thought they supported PASV, but didn't. They would
send a 227 reply with a malformed IP address or port number. Or they
would send a valid 227 reply, but then they would not listen on the
advertised port.
To make matters worse, we chose to implement the client's "FWFriendly"
command as a toggle. By the time we'd discovered there was a problem,
a number of customers had added the FWF command to their FTPs to turn
the new behavior off. If we reversed the default, we would cause all
those customers to revert to the unwanted behavior. We were stuck.
That was more than ten years ago now, and most of those server
implementations have probably been cleaned up, in large part because
of the problems exposed by firewall-friendly clients.
Still, the CS guys were wise to ignore the RFC and leave the old
default in place.
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