XDMCP connection failed for RH9 [1]

Can xstart an xterm - but trying to use Xmanager receive only the grey screen

from my xmanager.log on my pc:

XdmcpFill: too few bytes(-1) received
Xdmcp: Timed out, state 3. Retransmissions: 0
Xdmcp Query Address: 10.1.2.167
XdmcpFill: too few bytes(-1) received
Xdmcp: Timed out, state 3. Retransmissions: 1
Xdmcp Query Address: 10.1.2.167
XdmcpFill: too few bytes(-1) received
Xdmcp: Timed out, state 3. Retransmissions: 2
Xdmcp Query Address: 10.1.2.167
XdmcpFill: too few bytes(-1) received
Xdmcp: Timed out, state 3. Retransmissions: 3
XDM go to sleep: too many retransmissions

on linux box:
[xdmcp] from gdm.conf
# Distributions: Ship with this off. It is never a safe thing to leave
# out on the net. Alternatively you can set up /etc/hosts.allow and
# /etc/hosts.deny to only allow say local access.
Enable=true
# Enable=false (default setting)
Port=177

ran iptables -F to flush and was able to connect thru XManager

and then edit /etc/sysconfig/iptables by adding the lines in the FAQ #2 -
-A input -p udp -s 0/0 -d 0/0 177 -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 telnet -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 ssh -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 login -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 exec -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 shell -j ACCEPT
-A input -p tcp -s 0/0 -d 0/0 7100 -j ACCEPT