SLAC's
Policy on Connection of Multi-homed Hosts
Last Update: April 15, 1998
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Multi-homed hosts are becoming increasingly common, making it possible
to connect a host to more than one subnet simultaneously. This type of
configuration provides a number of advantages including better throughput,
reduced routing overhead and (possibly) secure communication between sensative
networks through a trusted host. However, although the connection of a
multi-homed host might be quite innocent and with the best intentions,
it can lead (and has been observed at SLAC) to disasterous results for
the network as a whole if it is configured incorrectly. In particular a
multihomed host acting as a router has the potential to cause unwanted
traffic possibly denying service to many users.
Please read the guidelines below before connecting a multi-homed host
to the SLAC LAN.
-
Always consult a member of the Network Development Group or send a message
to net-admin before attempting
to connect a multihomed host. You will be advised whether its OK to proceed.
-
No host should be connected to the network which is configured as a router.
-
If you have a multhomed host check with the manufacturer's documentation
to ensure that you understand how the operating system deals with multihoming.
-
As an example, on a Sun workstation running Solaris, routing is enabled
by default if
more than one network interface is detected. This can be avoided by placing
a file named norouter in /etc. For more information see "TCP/IP
and Data Communications Administration Guide (Solaris 2.5 System Administrator
AnswerBook), Page 86"
Dave Millsom
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