Re: MAC intermittently being learnt on wrong port

[Robert LeBlanc <robert@xxxxxxxxxxxxx>]

On Thu, Jan 7, 2010 at 8:25 PM, Ryan King <ryank@xxxxxxxxxxxxxxxxxxxx> wrote:

Hi,

 

I am seeing a strange issue with a fairly simple bridge I have setup (for openvpn in bridge mode).

 

eth0 ---  [ openvpn machine  (tap0) ] --- eth1

 

The bridge is between tap0 and eth1 on a debian machine running on ESX 4.  (tap0 being the openvpn tunnel interface).  Intermittently, I see openvpn client MAC addresses on port 2 (eth1).  When this happens, their vpn link stops working, since arp replies are being sent back via the wrong interface.  But after a random amount of time, it will change back to port 1 (tap0) and start working again.  Sometimes this is quick, sometimes it doesn't happen for hours.

 

Anyone else had these issues?  I've searched the archives, and come across several people who seem to have had similar problems - but haven't found one that has a solution yet.

 

I'd appreciate any suggestions on where I should start looking to find out why/how these MAC's are being learnt on the wrong interface...

 

 

brctl show br0:

 

bridge name      bridge id                              STP enabled       interfaces

br0                         8000.005056b804c2         no                           eth1

                                                                                                                tap0

 

 

brctl showstp br0:

 

br0

 bridge id                             8000.005056b804c2

 designated root              8000.005056b804c2

 root port                                0                                           path cost                                0

 max age                                20.00                                   bridge max age                   20.00

 hello time                             2.00                                     bridge hello time               2.00

 forward delay                     5.00                                     bridge forward delay        5.00

 ageing time                       300.01

 hello timer                           1.19                                     tcn timer                                0.00

 topology change timer    0.00                                     gc timer                                  2.19

 flags                                    

 

 

eth1 (2)

 port id                 8002                                       state                           forwarding

 designated root              8000.005056b804c2         path cost                             100

 designated bridge          8000.005056b804c2         message age timer            0.00

 designated port              8002                                       forward delay timer          0.00

 designated cost                  0                                           hold timer                             0.19

 flags                                    

 

tap0 (1)

 port id                 8001                                       state                           forwarding

 designated root              8000.005056b804c2         path cost                             100

 designated bridge          8000.005056b804c2         message age timer            0.00

 designated port              8001                                       forward delay timer          0.00

 designated cost                  0                                           hold timer                             0.19

 flags

 

 

eg:

brctl showmacs br0:

 

port no mac addr                             is local?                ageing timer

  2            00:50:56:b8:04:c2             yes                            0.00

  1            00:ff:46:97:7f:d5               yes                            0.00

  2            7a:6e:9f:28:12:79              no                              0.56

 

7a:6e:9f:28:12:79 -- the openvpn client

00:ff:....   -- tap0

00:50:56...   -- eth1

 

 

 

 

 

Thanks,

 

Ryan

I too am seeing this problem, I've tested with Lenny and Squeeze on ESX 4 and still see the same problem. I am anxiously awaiting some help on how to troubleshoot the problem. This is a big hang up for me. I don't know if the virtual switch is sending out multiple replies or what, I'm going to set this up on some physical hardware and compare. I don't know what else to do.

Thanks,

Robert LeBlanc
Life Sciences & Undergraduate Education Computer Support
Brigham Young University

 

_______________________________________________
Bridge mailing list
Bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/bridge