FTP problem between Symbolics and SUN3

["Eric S. Crawley" <Crawley@alderaan.scrc.symbolics.com>]

    Date: Mon, 05 Oct 87 21:10:41 +0900
    From: HONDA CAB <honda%titisa.is.titech.junet%utokyo-relay.csnet@relay.cs.net>

    Dear SLUG Readers,

    We have Symbolics 3620 and some SUN3s, which are connected via
    ethernet. The trouble is that, after coping a file from Symbolics to a
    SUN3, (yes, ftp finishes successfully on Symbolics side) the Unix side
    connection of network is still ESTABLISHED and never disconnect (I saw
    this from unix command netstat).

    Futhermore, on SUN3, the process in.ftpd (which is invoked from inetd)
    does not finishes. This causes serious problem of "process table full"
    on SUN3.

    Is this a known bug and does anyone have any fix , or is this a feature ?

    We use Genera7.01G, ip-tcp version 52, and SUN3-140 running SUN-OS 3.3.

A quick way to make these connections go away soon after your file
transfers are complete is to set the file-control-lifetime host
attribute in the SUN3's namespace object to a low value such as 10000.
The file-control-lifetime value is the amount of time, in 60ths of a
second, that a file connection is allowed to sit idle before the file
connection scavenger removes it.  If no value is specified, this
defaults to 1 or 2 hours (I can't remember which off the top of my
head).

There were some problems in 7.0 with FTP connections not being scavanged
properly.  Some of these were fixed for 7.1 but there are still some
timing windows that cause connections to be left hanging around.  In
most cases, it is just on the lispm side so it does not usually tie up
resources on the server.  Usually a small file-control-lifetime value
for the host makes sure that these connections are gone before they get
into a state that would leave them hanging.