Neighbour table overflow

Bridge WL Siew 5 participants 6 messages Jan 4, 2005 – Jan 6, 2005 Ethernet bridge

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WL Siew

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2005-01-04 17:39 UTC #0 lore raw

Hi,

I had successfully setup my bridge (br0) but after few minutes the br0 interface seems not working.

ifconfig eth0 0.0.0.0
ifconfig eth5 0.0.0.0

brctl addbr br0

brctl addif br0 eth0
brctl addif br0 eth5

brctl stp br0 on

I check on my system's /var/log/syslog file. It shows something strange messages as below: -

Jan  2 10:44:22 fw01 kernel: ipt_tcpmss_target: bad length (64 bytes)
Jan  2 10:44:32 fw01 last message repeated 11 times
Jan  2 12:27:08 fw01 kernel: Neighbour table overflow.
Jan  2 12:27:11 fw01 last message repeated 9 times
Jan  2 12:27:13 fw01 kernel: NET: 10 messages suppressed.

I unplug the network cable connected to the eth5 and run a ping to my router...the network is up again...I am able to ping my router.

Then, I plug the network cable to the eth5 interface again...I run the ping to my router and suddenly I can't ping my router. The same error messages pops out in the /var/log/syslog file.

How can I solve this issue?

Regards,
ro0ot

Christopher E. Cramer

2005-01-04 20:30 UTC #1 lore raw

we've had similar issues on a large scanning machine. nothing like trying to keep 100,000 entries in your arp cache.

try the following (at least under redhat w/ 2.4 kernels):

echo 100000 > /proc/sys/net/ipv4/neigh/default/gc_thresh3

this will increase the max size of the neighbor table to 100000

-c

--
Christopher E. Cramer, Ph.D.
Information Technology Security Officer Duke University, Office of Information Technology

Quoted 42 lines · WL Siew

Hi,
I had successfully setup my bridge (br0) but after few minutes the br0 interface seems not working.
ifconfig eth0 0.0.0.0
ifconfig eth5 0.0.0.0
brctl addbr br0
brctl addif br0 eth0
brctl addif br0 eth5
brctl stp br0 on
I check on my system's /var/log/syslog file. It shows something strange messages as below: -
Jan  2 10:44:22 fw01 kernel: ipt_tcpmss_target: bad length (64 bytes)
Jan  2 10:44:32 fw01 last message repeated 11 times
Jan  2 12:27:08 fw01 kernel: Neighbour table overflow.
Jan  2 12:27:11 fw01 last message repeated 9 times
Jan  2 12:27:13 fw01 kernel: NET: 10 messages suppressed.
I unplug the network cable connected to the eth5 and run a ping to my router...the network is up again...I am able to ping my router.
Then, I plug the network cable to the eth5 interface again...I run the ping to my router and suddenly I can't ping my router. The same error messages pops out in the /var/log/syslog file.
How can I solve this issue?
Regards,
ro0ot
_______________________________________________
Bridge mailing list
[email protected]
http://lists.osdl.org/mailman/listinfo/bridge

Bart De Schuymer

2005-01-04 21:04 UTC #2 lore raw

In reply to WL Siew

Op wo, 05-01-2005 te 01:39 +0800, schreef WL Siew:

Quoted 8 lines

Hi,
I had successfully setup my bridge (br0) but after few minutes the br0 interface seems not working.
ifconfig eth0 0.0.0.0
ifconfig eth5 0.0.0.0

Quoted 6 lines

brctl addbr br0
brctl addif br0 eth0
brctl addif br0 eth5
brctl stp br0 on

From the information you give, it seems that you assigned the IP address 0.0.0.0 to your bridge ports and you didn't to start the bridge itself. Your box therefore has no IP address and will therefore not respond to icmp messages.

Try

# ifconfig br0 $IP_ADDRESS
A ping to $IP_ADDRESS from another host should then work (after you
start the bridge it can take a few seconds before the bridge responds).

Quoted 8 lines

I check on my system's /var/log/syslog file. It shows something strange messages as below: -

Jan  2 10:44:22 fw01 kernel: ipt_tcpmss_target: bad length (64 bytes)
Jan  2 10:44:32 fw01 last message repeated 11 times
Jan  2 12:27:08 fw01 kernel: Neighbour table overflow.
Jan  2 12:27:11 fw01 last message repeated 9 times
Jan  2 12:27:13 fw01 kernel: NET: 10 messages suppressed.

Perhaps these are triggered by the fact that your network devices enter promiscuous mode.

Quoted 2 lines

I unplug the network cable connected to the eth5 and run a ping to my router...the network is up again...I am able to ping my router.

I'm assuming you are talking about the bridge box when you are talking about the router? The bridge ports of a bridge are by default not separately pingable. Only the IP address of the bridge (br0) device itself is pingable.
You can change that behaviour by making a brouter. You can then assign IP addresses to the bridge ports and use them.

cheers,
Bart

ro0ot

2005-01-05 00:40 UTC #3 lore raw

I had this line for the br0 IP address: -

ifconfig br0 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255

Regards,
ro0ot

Quoted 64 lines · Bart De Schuymer

Op wo, 05-01-2005 te 01:39 +0800, schreef WL Siew:
Quoted 9 lines
Hi,
I had successfully setup my bridge (br0) but after few minutes the br0 interface seems not working.
ifconfig eth0 0.0.0.0
ifconfig eth5 0.0.0.0
brctl addbr br0
Quoted 8 lines
brctl addif br0 eth0
brctl addif br0 eth5
brctl stp br0 on
From the information you give, it seems that you assigned the IP address
0.0.0.0 to your bridge ports and you didn't to start the bridge itself. Your box therefore has no IP address and will therefore not respond to icmp messages.
Try
# ifconfig br0 $IP_ADDRESS
A ping to $IP_ADDRESS from another host should then work (after you
start the bridge it can take a few seconds before the bridge responds).
Quoted 9 lines
I check on my system's /var/log/syslog file. It shows something strange messages as below: -
Jan  2 10:44:22 fw01 kernel: ipt_tcpmss_target: bad length (64 bytes)
Jan  2 10:44:32 fw01 last message repeated 11 times
Jan  2 12:27:08 fw01 kernel: Neighbour table overflow.
Jan  2 12:27:11 fw01 last message repeated 9 times
Jan  2 12:27:13 fw01 kernel: NET: 10 messages suppressed.
Perhaps these are triggered by the fact that your network devices enter promiscuous mode.
Quoted 3 lines
I unplug the network cable connected to the eth5 and run a ping to my router...the network is up again...I am able to ping my router.
I'm assuming you are talking about the bridge box when you are talking about the router? The bridge ports of a bridge are by default not separately pingable. Only the IP address of the bridge (br0) device itself is pingable.
You can change that behaviour by making a brouter. You can then assign IP addresses to the bridge ports and use them.
cheers,
Bart

ro0ot

2005-01-05 14:10 UTC #4 lore raw

Based on the result of the command "brctl showstp br0" below, what is the "designated bridge" means?

Something strange on this line "designated bridge 8000.000e6ae78720", this is because this is the MAC address of my 3Com 4400 switch which I have VLAN running and bridge too...

Will this cause the problem?

root@fw01:~# brctl showstp br0
br0
bridge id              8000.000c4120c1a6
designated root        8000.000bac2851c0
root port                 2                    path cost                136
max age                  20.00                 bridge max age            20.00
hello time                2.00                 bridge hello time          2.00
forward delay            15.00                 bridge forward delay      15.00
ageing time             300.00
hello timer               0.00                 tcn timer                  0.00
topology change timer     0.00                 gc timer                   0.90
flags

eth0 (1)

port id                8001                    state                forwarding
designated root        8000.000bac2851c0       path cost                100
designated bridge      8000.000c4120c1a6       message age timer          0.00
designated port        8001                    forward delay timer        0.00
designated cost         136                    hold timer                 0.00

flags

eth5 (2)

port id                8002                    state                forwarding
designated root        8000.000bac2851c0       path cost                100
designated bridge      8000.000e6ae78720       message age timer          3.08
designated port        800d                    forward delay timer        0.00
designated cost          36                    hold timer                 0.00

flags

Quoted 83 lines · ro0ot wrote:

I had this line for the br0 IP address: -
ifconfig br0 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255
Regards,
ro0ot
Quoted 58 lines · Bart De Schuymer
Op wo, 05-01-2005 te 01:39 +0800, schreef WL Siew:
Quoted 9 lines
Hi,
I had successfully setup my bridge (br0) but after few minutes the br0 interface seems not working.
ifconfig eth0 0.0.0.0
ifconfig eth5 0.0.0.0
brctl addbr br0
Quoted 8 lines
brctl addif br0 eth0
brctl addif br0 eth5
brctl stp br0 on
From the information you give, it seems that you assigned the IP address
0.0.0.0 to your bridge ports and you didn't to start the bridge itself. Your box therefore has no IP address and will therefore not respond to icmp messages.
Try
# ifconfig br0 $IP_ADDRESS
A ping to $IP_ADDRESS from another host should then work (after you
start the bridge it can take a few seconds before the bridge responds).
Quoted 8 lines
I check on my system's /var/log/syslog file. It shows something strange messages as below: -
Jan  2 10:44:22 fw01 kernel: ipt_tcpmss_target: bad length (64 bytes)
Jan  2 10:44:32 fw01 last message repeated 11 times
Jan  2 12:27:08 fw01 kernel: Neighbour table overflow.
Jan  2 12:27:11 fw01 last message repeated 9 times
Jan  2 12:27:13 fw01 kernel: NET: 10 messages suppressed.
Perhaps these are triggered by the fact that your network devices enter promiscuous mode.
Quoted 2 lines
I unplug the network cable connected to the eth5 and run a ping to my router...the network is up again...I am able to ping my router.
I'm assuming you are talking about the bridge box when you are talking about the router? The bridge ports of a bridge are by default not separately pingable. Only the IP address of the bridge (br0) device itself is pingable.
You can change that behaviour by making a brouter. You can then assign IP addresses to the bridge ports and use them.
Quoted 7 lines
cheers,
Bart
_______________________________________________
Bridge mailing list
[email protected]
http://lists.osdl.org/mailman/listinfo/bridge

Stephen Hemminger

2005-01-06 21:56 UTC #5 lore raw

Quoted 2 lines · On Wed, 05 Jan 2005 22:10:48 +0800 ro0ot <[email protected]> wrote:

Based on the result of the command "brctl showstp br0" below, what is the "designated bridge" means?

It means the the next step up the hierarchal spanning tree from this bridge. I.e where to send frames that aren't in the bridge forwarding table

Quoted 4 lines

Something strange on this line "designated bridge 8000.000e6ae78720", this is because this is the MAC address of my 3Com 4400 switch which I have VLAN running and bridge too...

Many switches use the same spanning tree protocol because they are really just bridges. The issue is they assume that any other bridge also sees all the traffic (and is not just on the VLAN).

You could try turning off STP but it might not help.

Quoted 142 lines

Will this cause the problem?
root@fw01:~# brctl showstp br0
br0
 bridge id              8000.000c4120c1a6
 designated root        8000.000bac2851c0
 root port                 2                    path cost                136
 max age                  20.00                 bridge max 
age            20.00
 hello time                2.00                 bridge hello 
time          2.00
 forward delay            15.00                 bridge forward 
delay      15.00
 ageing time             300.00
 hello timer               0.00                 tcn 
timer                  0.00
 topology change timer     0.00                 gc 
timer                   0.90
 flags
eth0 (1)
port id 8001 state
forwarding
 designated root        8000.000bac2851c0       path cost                100
 designated bridge      8000.000c4120c1a6       message age 
timer 0.00
designated port 8001 forward delay
timer 0.00
designated cost 136 hold
timer 0.00
flags
eth5 (2)
port id 8002 state
forwarding
 designated root        8000.000bac2851c0       path cost                100
 designated bridge      8000.000e6ae78720       message age 
timer 3.08
designated port 800d forward delay
timer 0.00
designated cost 36 hold
timer 0.00
flags
Quoted 82 lines · ro0ot wrote:
I had this line for the br0 IP address: -
ifconfig br0 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255
Regards,
ro0ot
Quoted 62 lines · Bart De Schuymer
Op wo, 05-01-2005 te 01:39 +0800, schreef WL Siew:
Quoted 13 lines
Hi,
I had successfully setup my bridge (br0) but after few minutes the br0 interface seems not working.
ifconfig eth0 0.0.0.0
ifconfig eth5 0.0.0.0
brctl addbr br0
brctl addif br0 eth0
brctl addif br0 eth5
Quoted 6 lines
brctl stp br0 on
From the information you give, it seems that you assigned the IP address
0.0.0.0 to your bridge ports and you didn't to start the bridge itself. Your box therefore has no IP address and will therefore not respond to icmp messages.
Try
# ifconfig br0 $IP_ADDRESS
A ping to $IP_ADDRESS from another host should then work (after you
start the bridge it can take a few seconds before the bridge responds).
Quoted 9 lines
I check on my system's /var/log/syslog file. It shows something strange messages as below: -
Jan  2 10:44:22 fw01 kernel: ipt_tcpmss_target: bad length (64 bytes)
Jan  2 10:44:32 fw01 last message repeated 11 times
Jan  2 12:27:08 fw01 kernel: Neighbour table overflow.
Jan  2 12:27:11 fw01 last message repeated 9 times
Jan  2 12:27:13 fw01 kernel: NET: 10 messages suppressed.
Perhaps these are triggered by the fact that your network devices enter promiscuous mode.
Quoted 3 lines
I unplug the network cable connected to the eth5 and run a ping to my router...the network is up again...I am able to ping my router.
I'm assuming you are talking about the bridge box when you are talking about the router? The bridge ports of a bridge are by default not separately pingable. Only the IP address of the bridge (br0) device itself is pingable.
You can change that behaviour by making a brouter. You can then assign IP addresses to the bridge ports and use them.
Quoted 7 lines
cheers,
Bart
Quoted 5 lines
_______________________________________________
Bridge mailing list
[email protected]
http://lists.osdl.org/mailman/listinfo/bridge
_______________________________________________
Bridge mailing list
[email protected]
http://lists.osdl.org/mailman/listinfo/bridge