ifadmin(1M) ifadmin(1M)
NAME
ifadmin - administration tool for alias interfaces
SYNOPSIS
ifadmin -i interface -a system [-n aliasname]
ifadmin -d system
ifadmin -l
ifadmin -i interface -R
DESCRIPTION
ifadmin is a tool for administration of alias IP interfaces. It is
used to configure virtual interfaces as an alias to an existing inter-
face, delete aliased interfaces, or list existing aliased interfaces.
COMMANDS
ifadmin -i interface -a system [-n aliasname]
This command creates a virtual interface as an alias of an exist-
ing interface and assigns to it a new IP address.
interface
Name of a configured networking interface, e.g. lce1. The
names lo0 and arp0 must not be used here.
system
Name of a system that can be resolved to an IP address, or
an IP address in dotted quad notation, e.g. rhodos-A or
139.27.38.2.
aliasname
Name for the aliased interface, e.g. lce1-sysA. By conven-
tion, the name of the aliased interface starts with
interface-. interface is the name of the physical interface
for which the alias is specified. This will help you to see
immediately for which physical interface this is an alias.
If -n aliasname is not specified, an internal unique name
of the form interface-X is generated, where X is a number
between 1 and 999.
Example:
ifadmin -i lce1 -a 139.27.38.2 -n lce1-sysA
Create an alias for interface lce1. The name of the new interface
will become lce1-sysA, the interface is assigned the IP address
139.27.38.2. The hardware address of the new interface is the
hardware address of lce1.
Once an alias interface is created the system will respond to ARP
requests for the IP address of that interface.
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Restrictions:
The original interface that is aliased must be configured and
active. It must not be an aliased interface.
Aliased interfaces are not complete IP interfaces. There are no
interface statistics available for an aliased interface, the
statistics are recorded in the counters of the original inter-
face.
The netstat -i command displays the alias interfaces under the
name of the original interface as well as their statistics. The
"Network" and "Address" columns show the values used in the con-
figuration of the alias interfaces.
The netstat -p command lists all alias interfaces under their
real names.
Aliases are recognized by having the ALI flag set.
Alias interfaces may also be listed with ifadmin -l.
ifadmin -d system
This command is used to delete a previously configured alias
interface.
system
Name of a system that can be resolved to an IP address, or
an IP address in dotted quad notation, e.g. rhodos-A or
139.27.38.2. This is the IP address of the alias interface
to be deleted.
Example:
ifadmin -d 139.27.38.2
This deletes the alias interface configured above.
Note:
When a real IP interface is deconfigured, all interfaces that are
aliases of this interface are also deleted.
ifadmin -l
This command prints a list of alias interfaces.
Example:
ifadmin -l
Output:
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Interface Alias Physical
lce1-sysA 139.27.38.2 8:0:8b:1e:20
Note:
The alias address is the IP address of the alias interface. The
hardware (physical) address is the address of the real interface.
ifadmin -i interface -R
This command sends an unsolicited ARP reply on behalf of the
specified interface. The interface's hardware and IP addresses
will become the source hardware and IP addresses, respectively,
in the ARP reply.
interface
The name of the interface to be used in the ARP reply. The
configured addresses of the specified interface will be used
for the ARP reply.
The usual requirement is to send the ARP reply for an alias
interface. In such cases interface will specify the alias inter-
face and not the real one.
EXAMPLES
ifadmin -i lce1 -a 139.27.38.2 -n lce1-sysA
This will create an alias lce1-sysA for interface lce1 and assign
it the IP address 139.27.38.2.
ifadmin -l
Output:
Interface Alias Physical
lce1-sysA 139.27.38.2 8:0:8b:1e:20
The alias interface lce1-sysA has the IP address 139.27.38.2 and
the hardware address 8:0:8b:1e:20.
netstat -p
Output:
Interface Address Netmask Broadcast Flags
lo0 localhost 0xff000000 none UP,LOOP,NTRAILER,RUN
lce1 139.27.38.4 0xffffff00 139.27.38.255 UP,BCAST,NTRAILER
lceS1 none none none BCAST,NTRAILER
lce1-sysA 139.27.38.2 0xffffff00 139.27.38.255 UP,BCAST,NTRAILER,ALI
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ifadmin -i lce1-sysA -R
This will trigger an unsolicited broadcast ARP reply with IP
source address 139.27.38.2 and source hardware address
8:0:8b:1e:20. Most ARP implementations on systems connected to
the same physical network will update their ARP table entry for
IP address 139.27.38.2 to use the hardware address 8:0:8b:1e:20.
SEE ALSO
ifconfig(1M), inet(4).
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