Restrictions And Recommendations - HP -UX B6941-90001 Administrator's Reference Manual

The Message Receiver on the server registers TCP/UDP port 1200 in
its unique RPCD/LLBD and listens there for ITO traffic.
The Distribution Manager on the server registers TCP/UDP port
1051 in its unique RPCD/LLBD and listens there for ITO traffic.
RPC clients doing lookups in the RPCD/LLBDs find this information
and request connections to the Control Agent, Message Receiver and
so on at the port numbers listed.
Note that, in addition to allowing you to restrict the allocation of port
numbers, ITO also allows you to work through firewalls that implement
NAT (Network Address Translation) by configuring the file
/opt/OV/share/conf/OpC/mgmt_sv/opc.hosts on the ITO
management server in the following manner:
<alternative_ip_address> <agent_node_name_known_to_the_server>
In the ITO GUI, you set up the ITO node with the IP-address that the
ITO server knows through its DNS-server or hostname resolution. In the
opc.hosts file, you tell the ITO management server that it should
accept another IP-address for this node.

Restrictions and Recommendations

If the systems participating in the ITO environment are connected via a
fast network (LAN), it is generally recommended that you choose UDP
rather than TCP as the DCE RPC protocol. UDP requires significantly
less overhead and is therefore faster and less demanding of resources. If
the managed nodes and management server are connected over a slow or
busy network (WAN, X.25 etc.), or even if the volume of data to be
transmitted is large, it is more reliable to use TCP. Note that TCP
requires at least one socket to be permanently open for each managed
node.
However, if you do choose the DCE RPC (UDP) option as the
communication type between managed node and management server,
you should bear in mind that ITO's configuration distribution and
Common Agent bulk transfer both require a plain TCP socket connection
to be open. So, if for example a packet-filtering firewall system is located
between a management server and managed node communicating via
DCE RPC (UDP) and the firewall has a specific range of ports opened
(reflected in the ITO configuration), this range must always be open for
TCP, too.
Chapter 9
An Overview of ITO Processes
Secure Networking
371