strange networking behaviour with a bridge in game

hi list

I have a strange problem here. Maybe it is normal behavior and i search within the wrong direction. Probably someone here can give me a hint.

I have a device (rhel4 kernel 2.6.9) with 3 interfaces. 2 interfaces (eth0, eth2) are bridged together (br0) and the bridge device has an ip address assigned (192.168.11.15).
Another interface (eth1) has assigned 10.7.0.10.

So far so good. Everything is working well if traffic passes from 192.168.11.0/24 out to 10.7.0.0/24 if both networks are on different switches.

The thing begins to become strange if both eth0 and eth1 are connected on the same switch (eth2 is not connected). So i have both subnets on the same switch (for testing purposes).
If i then would like to access 192.168.11.15, packets reach the device through the interface eth1 instead of eth0/br0, which in fact is wrong. The arp table on the client shows this also. 192.168.11.15 is assigned to the mac adress of the interface eth1.

Needless to say that this happens only from time to time. If i cleanup the arp table sometimes it went alright.

What's wrong with my installation?

Thank you in advance!

peter

:: e n d i a n
:: open source - open minds

:: peter warasin
:: http://www.endian.com   :: [email protected]

Check out the ip sysctl/proc arp_ignore

net.ipv4.conf.tun0.arp_ignore = 0
net.ipv4.conf.eth0.arp_ignore = 0
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.all.arp_ignore = 0

or

/proc/sys/net/ipv4/conf/tun0/arp_ignore
/proc/sys/net/ipv4/conf/eth0/arp_ignore
/proc/sys/net/ipv4/conf/lo/arp_ignore
/proc/sys/net/ipv4/conf/default/arp_ignore
/proc/sys/net/ipv4/conf/all/arp_ignore

arp_ignore - INTEGER
Define different modes for sending replies in response to received ARP requests that resolve local target IP addresses:
0 - (default): reply for any local target IP address, configured on any interface
1 - reply only if the target IP address is local address configured on the incoming interface
2 - reply only if the target IP address is local address configured on the incoming interface and both with the sender's IP address are part from same subnet on this interface 3 - do not reply for local addresses configured with scope host, only resolutions for global and link addresses are replied 4-7 - reserved
8 - do not reply for all local addresses

The max value from conf/{all,interface}/arp_ignore is used when ARP request is received on the {interface}

hi andy

wow!
this solved my problem.
thank you very much for your answer!

i will raise a statue for you :)

peter

:: e n d i a n
:: open source - open minds

:: peter warasin
:: http://www.endian.com   :: [email protected]

Hahahaha! Glad that helped you out! :-)