On Wednesday, 07/02/2008 at 03:57 EDT, "Schuh, Richard" <[EMAIL PROTECTED]> wrote: > Near the end of a 605MB (the size of the VMARC file; unpacked, it is over > 2.7GB) FTP, I got the message "421 Service not available, closing control > connection." Dumb me, I looked in the numbered client and server messages and > could not find a 421. Then I looked in the section called "Reply Code Messages" > and found a 421 with different text.
The text comes from the server. The architected part of the response is the "421", telling the client what to do. > It says to issue an Open command to > reestablish connection with the server. This brings to mind a couple of > questions with my guesses in parentheses: > > Is there any point in resuming the connection if all I was doing was sending > one file? (probably not) > If I do reestablish the connection, will the FTP be resumed, picking up where > it was when the connection was lost ? (no) No, there's no point since both ends would have to support the FTP "restart" function. z/VM doesn't. > What is needed in the way of an Open command? (irrelevant if my first 2 guesses > are correct) I entered no such command initially, I entered an FTP command, > answered the userid and password prompts, then entered the commands BIN and PUT. > I the loss of service appears to have been outside of VM. Is there any way to > determine if the loss was at the vendor's server or somewhere between the two > endpoints? Only by gathering packet traces on both sides of your proxy firewall. If RESET or CLOSE packets are sent in two directions, it indicates that the firewall terminated your session. The OPEN subcommand is used to establish a session when you're already in the FTP client. Alan Altmark z/VM Development IBM Endicott
