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Date:	Wed, 2 Apr 2014 11:25:42 +0200
From:	Albert Krenz <>
Subject: Cannot delete entries from bridge fdb

Hello everyone,
i have a question concerning the forwarding database (fdb) of the
bridges. I am using:
- Ubuntu 13.10
- kernel 3.11.0 from ubuntu repos
- bridge utility 0.0 from iproute2 package
- bridge-utils 1.5

I have 3 applications, each one creating a tap (tap0 - tap2) which i
add to the bridge br0. Two Applications are receiving Frames (app0 and
app1) and the third one (app2) sends one Frame every second to app0.
SRC and DST MAC are different from the tap MAC's. App0 sends an answer
to app2 and the bridge adds an entry to his fdb with the MAC of app0
on tap0.

Now i wanted to delete this entry which does not work. RTNETLINK tells
me there is no file or directory. See the following example:

root@...c:~# bridge fdb show dev tap0
33:33:00:00:00:01 self permanent
01:00:5E:00:00:01 self permanent
40:EC:F8:03:A7:B5 vlan 0
              << i want to delete this one
9A:0D:06:68:5D:75 vlan 0 permanent
         << MAC of tap0
root@...c:~# bridge fdb del 40:EC:F8:03:A7:B5 vlan0 dev tap0
RTNETLINK answers: No such file or directory

If i add a random entry i can delete it without any problem.

root@...c:~# bridge fdb add 40:EC:F8:03:A7:FF vlan0 dev tap0
root@...c:~# bridge fdb del 40:EC:F8:03:A7:FF vlan0 dev tap0
                << this works

Is there another syntax to delete entries which the bridge has added
by himself? Or is it not possible to delete entries which you haven't
added by hand?

Albert Krenz
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