I took mitchema's instructions for Network HOTSYNC for SPRINT TREO 300 and updated then for Cingular TREO 650:

ON YOUR COMPUTER (assumes a PC):

1. Make sure HOYSYNC MANAGER is set to run when your computer starts up.

a) to do this click on hotsync manager icon near time
b) choose setup
c) go to the tab marked GENERAL
d) make sure a check mark appears before the words
' ALWAYS AVAILABLE (PUT IN STARTUP FOLDER)

2. Make sure HOYSYNC MANAGER is set to accept TCP/IP Network request to sync.

a) to do this click on hotsync manager icon near time
b) make sure a check mark appears before the word network

3. Make sure HOYSYNC MANAGER is setup on your network.

a) to do this click on hotsync manager icon near time
b) choose setup
c) go to the tab marked NETWORK
d) make sure a check mark appears before the user who
wants to sync over the internet.
e) click on the button marked 'TCP/IP SETTINGS...'
f) To speed syncing enter your computers subnet mask if
known. ( TIP! running the command 'ipconfig /all' in DOS
shows the subnet mask)
g) With Hotsync manager 6.0 this may not be necessary, it seems to find the TCP/IP settings for you.

ON YOUR TREO 650:

I. Set up HOTSYNC for Network Mode!
A) If not in Hotsync app click on the hotsync icon
B) under HOTSYNC Options click on MODEM SYNC PREFS
you can also just press O
C) choose NETWORK
D) press OK

II. Set up HOTSYNC for Lansync!
A) If not in Hotsync app click on the hotsync icon
B) under HOTSYNC Options click on LANSYNC PREFS
you can also just press L
C) choose LANSYNC
D) press OK

III. Set up HOTSYNC to connect to you PC
A) If you have a cradle and do a HOTSYNC by pushing the CRADLE HOTSYNC button it will do a local sync and transfer all of PRIMARY PC SETUP information to your TREO 650.
B) If not in Hotsync app click on the hotsync icon
C) Under HOTSYNC Options click on PRIMARY PC SETUP
you can also just press P
D) Under PRIMARY PC NAME:
1) enter "!!" (Replace the actual PRIMARY PC NAME that may have been transferred over during a local HOTSYNC, this is very important)
E) Under PRIMARY PC ADDRESS:
1) enter your PC's IP address
TIP! on windows 9x,ME,XP,2000 to get your address press
START->then press->under OPEN: type COMMAND->
and press OK. In the DOS box that opens type
IPCONFIG. Your IP address is shown. type EXIT to get
out of dos. (If you did step A on a TREO 650 this step will not be necessary)
F) Under SUBNET MASK (OPTIONAL) :
1) enter your PC's Subnet Mask address
TIP! on windows 9x,ME,XP,2000 to get your address press
START->then press->under OPEN: type COMMAND->
and press OK. In the DOS box that opens type
IPCONFIG /ALL. Your Subnet Mask is shown.
type EXIT to get out of dos. (If you did step A on a TREO 650 this step will not be necessary)

IV. Set up HOTSYNC for what you want to sync!
A) If not in Hotsync app click on the hotsync icon
B) under HOTSYNC Options click on CONDUIT SETUP
you can also just press D
C) By default all your applications are checked
D) You may wish to speed up syncing by unchecking apps you
dont want synced. ( BE WARNED, this type of SYNC seems to take 20x-100x longer than a local SYNC, it is prudent to consider only syncing what you really need.)

V. Set up HOTSYNC for the TREOs STANDARD MODEM
A) If not in Hotsync app click on the hotsync icon
B) under HOTSYNC Options click on CONNECTION SETUP
you can also just press S
C) By default STANDARD MODEM is highlighted.
If not click on STANDARD MODEM.
D) press DONE

VI. Set up HOTSYNC for the CINGULAR GPRS network
A) If not in Hotsync app click on the hotsync icon
B) select MODEM instead of local.
C) under the icon of the phone and hotsync click on the
dashed box. probably labeled select service.
D) You are taken to the network preferences screen.
E) Be sure the Service is listed as cingular GPRS
F) Choose done

VII. SYNC YOUR HANDHELD WHILE YOUR IN FRONT OF YOUR PC
A)If not in Hotsync app click on the hotsync icon
B)Press the phone and hotsync logo to begin the sync.
C) you will see the words "connecting with the desktop"
D) you will see the works "identifying user..."
E) On your desktop you may be prompted to select a User
Name for this sync. Choose your username.

If it works twice. Be confident it will work when you need it. Just have to keep your PC on!

*ROUTER OWNERS OR REMOTE SYNCERS USING NAT OR
FIREWALL:
ROUTER CONFIGURATION:
- Be sure to configure your firewall to open up TCP ports 14237 and UDP ports 14238. If you cant specify just choose 14237 and 14238. (On some routers you may have to specify the application as well, that is HOTSYNC.EXE.)
- Be sure that all traffic to those ports goes to the ip of the LAN PC that is running HOT SYNC MANAGER. (This is the IP Address you should get automatically in step III A, above. Most likely it will be an address like: 192.168.xxx.xxx)

TREO 650 CONFIGURATION
- Remember the IP address in step III part E has to be a WAN address not a private or internal LAN IP address, like 192.168.xxx.xxx. Therefore obtain the Router’s WAN address and enter it into the TREO 650 by repeating step III E above.
-
- After a successful sync the WAN IP address and the PRIMARY PC NAME will remain but you will get the following warning you will need to respond to when you execute Local HOTSYNCS. “The PC that is designated for your network HOTSYNC operation is called your Primary PC Another PC is designated as your Primary PC. Make this PC your Primary Hotsync PC? Answer YES