Opened 8 years ago

Closed 8 years ago

Last modified 4 years ago

#6423 closed defect (fixed)

Auto generated MACs on virtual interfaces are not random

Reported by: Stefan Bethke <stb@…> Owned by: developers
Priority: normal Milestone: Barrier Breaker 14.07
Component: kernel Version: Trunk
Keywords: mac bridge tap Cc:


MAC addresses assigned to virtual interfaces (br, tap) are not random, but consistent and stable. This means that two machines with similar configurations will generate the same MAC address for i.e. br-lan, which in turn means they cannot be connected to the same broadcast domain.

This is on r18794.

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Change History (5)

comment:1 Changed 8 years ago by Stefan Bethke <stb@…>

Assigning a custom MAC address to the bridge cannot be used as a work-around, since it breaks the bridge, see #6424.

comment:2 Changed 8 years ago by Stefan Bethke <stb@…>

There definitely is something fishy here. I'm getting a MAC address of 00:03:7F:BF:17:8E on br-lan, which according to include/linux/etherdevice.h:random_ether_addr should have bit 1 of the first octet set (i.e. the first byte should be 0x02 not 0x00).

comment:3 Changed 8 years ago by Stefan Bethke <stb@…>

Nevermind, this is pilot error due to trying to work around some bug with reading out the MAC address for the radio. After upgrading to r18957, all issues have disappeared.

comment:4 Changed 8 years ago by florian

  • Resolution set to fixed
  • Status changed from new to closed

comment:5 Changed 4 years ago by jow

  • Milestone changed from Attitude Adjustment 12.09 to Barrier Breaker 14.07

Milestone Attitude Adjustment 12.09 deleted

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