I have had  nat working and I move my monitor to adjust it and pulled 
the cord out of my computer and I haven't go it to work since.
It doesn't seem to be a hardware problem because I can ssh to it and in 
fact the other computer can access the dns, but the other computer can't 
make a tcp connection through the nat.

Here are my setup files.
Should any of these be +x (execute) they weren't and I haven't changed 
them but it quit working.


#!/sbin/sysctl -f
#
# $NetBSD: sysctl.conf,v 1.5 2003/11/03 15:12:06 briggs Exp $
#
# sysctl(8) variables to set at boot time.

# Default core name template:
#kern.defcorename=%n.core

# Number of kernel threads to use for NFS client
#vfs.nfs.iothreads=4
net.inet.ip.forwarding=1
net.inet.tcp.recvspace=65535
net.inet.tcp.sendspace=65535
 




# Load the defaults in from /etc/defaults/rc.conf (if it's readable).
# These can be overridden below.
#
if [ -r /etc/defaults/rc.conf ]; then
        . /etc/defaults/rc.conf
fi

# If this is not set to YES, the system will drop into single-user mode.
#
rc_configured=YES

# Add local overrides below
#
wscons=YES
hostname=shop
auto_ifconfig=YES
ifconfig_sip0="inet 192.168.0.1 netmask 255.255.255.0"
ipfilter=YES
ipnat=YES
named=YES
sshd=YES
sendmail=NO
#inetd=NO

#ipnat.conf
map ppp0 192.168.0.0/24 -> 0/32 proxy port ftp ftp/tcp
map ppp0 192.168.0.0/24 -> 0/32 portmap tcp/udp 40000:60000
map ppp0 192.168.0.0/24 -> 0/32


#ipf.conf
pass in from any to any
pass out from any to any