Specifications

Table Of Contents
VMware Server Virtual Machine Guide
176 VMware, Inc.
To!prevent!the!leakage,!be!sure!packet!forwarding!is!disabled!in!your!guest!operating!
system.
Maintaining and Changing the MAC Address of a Virtual
Machine
When!a!virtual!machine!is!powered!on,!VMware!Server!automatically!assigns!each!of!
its!virtual!network!adapters!an!Ethernet!MAC!address.!MAC!stands!for!media!access!
control.!A!MAC!address!is!the!unique!address!assigned!to!each!Ethernet!device.
The!software!guarantees!that!virtual!machines!are!assigned!unique!MAC!addresses!
within!
a!given!host!system.!In!most!cases,!the!virtual!machine!is!assigned!the!same!
MAC!address!every!time!it!is!powered!on,!so!long!as!the!virtual!machine!is!not!moved!
(the!path!and!filename!for!the!virtual!machine’s!configuration!file!must!remain!the!
same)!and!no!changes!are!made!to
!certain!settings!in!that!file.
In!addition,!VMware!Server!does!its!best,!but!cannot!guarantee,!to!automatically!assign!
unique!MAC!addresses!for!virtual!machines!running!on!multiple!host!systems.!
Avoiding MAC Address Changes
To!avoid!changes!in!the!MAC!address!automatically!assigned!to!a!virtual!machine,!you!
must!not!move!the!virtual!machine’s!configuration!file.!Moving!it!to!a!different!host!
computer!or!even!moving!it!to!a!different!location!on!the!same!host!computer!changes!
the!MAC!address.
You!also!need!to!be!
sure!not!to!change!certain!settings!in!the!virtual!machine’s!
configuration!files.!If!you!do!not!edit!the!configuration!file!by!hand!and!do!not!remove!
the!virtual!Ethernet!adapter,!these!settings!remain!untouched.!If!you!do!edit!the!
configuration!file!by!hand,!be!sure!not!to!remove!or!change!the
!following!options:
ethernet[n].generatedAddress
ethernet[n].addressType
ethernet[n].generatedAddressOffset
uuid.location
uuid.bios
ethernet[n].present
In!these!options,![n]!is!the!number!of!the!virtual!Ethernet!adapter,!for!example!
ethernet0.
NOTE To!preserve!a!virtual!Ethernet!adapter’s!MAC!address,!you!also!must!be!
careful!not!to!remove!it.!If!you!remove!the!adapter,!then!recreate!it,!it!might!
be!assigned!a!different!MAC!address.