Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Setting Up and Administering an HP-UX NFS Diskless Cluster
Configuring a Relay Agent
Chapter 10 915
Configuring a Relay Agent
It is likely that most or all of your NFS cluster’s clients are attached to
the same subnetwork as your cluster server. If not, a gateway (a device
such as a router, or a computer) can be used to connect two or more
networks.
Once a gateway is attached, the server can boot clients that are on
subnetworks that the server is not directly attached to. There can only be
one gateway that separates the server from the remote client.
A relay system is a computer that is on the same subnetwork as the
clients to be booted. A relay agent is software on the relay system and
server that is configured to pass client and server messages between the
two subnetworks.
There are some restrictions in setting up a relay system:
• The relay system must be a Series 700 or Series 800 computer in the
same subnet as the client. This machine must be running HP-UX
10.01 (or later) from a local file system; that is, it cannot itself be a
client of another NFS cluster.
• The client must be only one hop from the server; that is, the client
and server subnetworks must be connected through a single router
or gateway. You can verify this by running /usr/sbin/ping with the
-o option from the relay system to the server. For example, to check
the hops from tinkrbel to peter:
tinkrbel: /usr/sbin/ping -o peter -n 1
PING peter.neverlnd.com: 64 byte packets
64 bytes from 153.13.115.149: icmp_seq=0. time=18. ms
peter.neverlnd.com PING Statistics
1 packets transmitted, 1 packets received, 0% packet loss
round-trip (ms) min/avg/max = 18/18/18
1 packets sent via:
153.13.112.1 - croc-gw.neverlnd.com
153.13.115.149 - peter.neverlnd.com
153.13.104.1 - croc-gw.neverlnd.com
153.13.105.109 - tinkrbel.neverlnd.com
Note that the packet went from the relay system tinkrbel via the
gateway croc-gw to the server peter and returned back to tinkrbel
via croc-gw. This shows that tinkrbel is only one gateway
(croc-gw) away from peter.