Technical data

Configuring Interfaces
2.3 Configuring Network Interfaces
For this
controller Use this interface class
X25 X
Local (loopback) O
• An integer indicating the controller number. Controller numbers are decimal
numbers in the range of 0 through 25, corresponding to OpenVMS hardware
controller letters A through Z. The default is 0.
Primary interfaces for Ethernet controllers have names in the range SE, SE0,
SE1, SE2, . . . SE24, SE25.
Interfaces for PPP controllers have names in the range PP, PP0, PP1, . . . PP998,
PP999.
Interfaces for local (loopback) controllers have names in the range LO, LO0,
LO1, . . . L08, L09
Note
OpenVMS network devices are always template devices and are
enumerated as FWA0, FWB0, FWC0, . . . FWY0, FWZ0.
2.3.2 Specifying the Network Mask
An IP address consists of a network number and a host number. The network
mask is the part of the host field of the IP address the identifies the network.
Every host on the same network must have the same network mask. To specify
the network mask, use the /NETWORK_MASK qualifier.
TCP/IP Services calculates the default by setting:
• The bits representing the network fields to 1
• The bits representing the host field to 0
You can also divide the host field into a site-specific network and host field.
2.3.3 Specifying Additional IP Addresses
To establish an additional IP address for an interface, define a network alias.
This can be useful when changing network numbers and you want to continue
to accept packets addressed to the old interface, or for setting up a host with a
single interface to act as a router between subnets. Network aliases can be added
in two functionally identical ways:
• Associate multiple addresses to an existing interface.
You can use the ifconfig utility to associate multiple addresses with an
existing interface. There is no limit to the number of aliases that can be
created, and ranges of network addresses can be easily created. You should
include the
ifconfig command in SYS$STARTUP:TCPIP$SYSTARTUP.COM
to ensure the network aliases are re-created whenever TCP/IP Services is
restarted.
Configuring Interfaces 2–3