Hi David,
From the node's perspective, there are several ways you can restrict the node's connection to a specific on interface of the server:
1) When server discovery is enabled ("jppf.discovery.enabled = true", which is the default, in both node and server configuration).
The discovery mechanism consists in having the server broadcasting its connection information for all available network interfaces via UDP multicast. The nodes will listen to UDP datagrams sent broadcast by the server and connect to the first reachable server interface for which they receive information. JPPF offers 2 ways to restrict/filter which interfaces should be used.
a) You can specify
IP filters in the node's configuration
For instance, for the node to only connect on the server's eth0 interface, you could specify in the config:
# allow only IPv4 addresses in the range [10.1.1.1 ... 10.1.1.2] or 10.1.2.1
jppf.discovery.include.ipv4 = 10.1.1.1-2, 10.1.2.1
# (alternatively) exclude undesired 192.168.1.xxx addresses
jppf.discovery.exclude.ipv4 = 192.168.1
# exclude all IPv6 addresses
jppf.discovery.exclude.ipv6 = -
b) you might also want to
limit the interfaces the server is broadcasting to:
# broadcast information only for eth0 interface
jppf.discovery.broadcast.include.ipv4 = 10.1.
# (alternatively) exclude undesired 192.168.1.xxx addresses
jppf.discovery.broadcast.exclude.ipv4 = 192.168.1
# do not broadcast information for IPv6 addresses
jppf.discovery.broadcast.exclude.ipv6 = -
You may also combine a) and b) if your heart is at it

2) Disable server discovery ("jppf.discovery.enabled = false") in the server, the node or both.
In this case, you have to explicitely configure the host name or IP address you want the node to connect to, e.g. with "jppf.server.host = 10.1.1.1". When discovery is enabled for the node, this configuration property is ignored
I hope this clarifies.
Sincerely,
-Laurent