Sup has been failing for me too.  The symptoms are quite similar to
what others have reported; stderr is

SUP: Read error on network: Connection reset by peer
SUP: Premature EOF on network input
SUP: Network write timed out
SUP: Network write timed out

and stdout (for Thursday morning's run) is

/local/sup/bin/sup -B -d -E -K -o -z -v /sources/sup/supfiles/netbsd
SUP 8.26 (4.3 BSD) for file /sources/sup/supfiles/netbsd at Dec 14 04:30:02
SUP Upgrade of current-allsrc at Thu Dec 14 04:30:08 1995
SUP Fileserver 8.13 (4.3 BSD) 18610 on netbsd.warped.com at 04:30:08
SUP Requesting changes since Dec 10 08:09:06 1995
SUP Deleted file src/sys/arch/vax/mba/hpdefs.h
SUP Using compressed file transfer
SUP Updating file src/Makefile
SUP Updating file src/bin/date/date.1
SUP Updating file src/bin/df/df.1
SUP Updating file src/bin/df/df.c
SUP Updating file src/bin/ls/ls.1
SUP Updating file src/bin/ps/Makefile
SUP Updating file src/bin/sh/Makefile
SUP Updating file src/bin/sh/cd.c
SUP Updating file src/bin/sh/cd.h
SUP Updating file src/bin/sh/input.c
SUP Updating file src/bin/sh/main.c
SUP Updating file src/bin/sh/parser.c
SUP Updating file src/distrib/alpha/README.files
SUP Updating file src/distrib/alpha/rz25dist/Makefile
SUP Updating file src/distrib/amiga/floppies/inst-common/Makefile.inc
SUP Updating file src/distrib/amiga/floppies/inst-common/dot.commonutils
SUP Updating file src/distrib/amiga/floppies/inst-common/list
SUP Updating file src/distrib/amiga/floppies/inst/list
SUP Updating file src/distrib/amiga/floppies/upgr/list
SUP Updating file src/distrib/atari/Makefile.inc
SUP Updating file src/distrib/atari/inst-common/dot.commonutils
SUP Updating file src/distrib/crunch/crunchide/crunchide.c
SUP: Error receiving file from file server
SUP: Upgrade of current-allsrc aborted at Dec 14 04:36:07 1995
SUP: Aborted
SUP Upgrade of current-doc at Thu Dec 14 04:36:07 1995
SUP Fileserver 8.13 (4.3 BSD) 18633 on netbsd.warped.com at 04:36:07
SUP Requesting changes since Dec 12 08:04:48 1995
SUP Using compressed file transfer
SUP Updated directory doc
SUP Upgrade of current-doc completed at Dec 14 04:36:09 1995
done

Except for the dates and times, the "Deleted file" line for
vax/mba/hpdefs.h, and a "Receiving file doc/CHANGES" in the upgrade of
current-doc, the same happened this morning.  Basically the same thing
has been happening for about a week.

The supfile is the same one that's been working fine ever since the
move to warped.com:

current release=allsrc host=sup.netbsd.org hostbase=/ftp/pub base=/sources/sup/sup/netbsd prefix=/sources/supped/netbsd use-rel-suffix
current release=doc host=sup.netbsd.org hostbase=/ftp/pub base=/sources/sup/sup/netbsd prefix=/sources/supped/netbsd use-rel-suffix
#current release=security host=sup.netbsd.org hostbase=/ftp/pub base=/usr prefix=/usr backup use-rel-suffix
#current release=othersrc host=sup.netbsd.org hostbase=/ftp/pub base=/usr prefix=/usr backup use-rel-suffix

I hope someone can either point out what I'm doing wrong or fix
whatever's wrong on the server side, because this is getting annoying,
at least.

					der Mouse

			    mouse@collatz.mcrcim.mcgill.edu