FreeBSD Bridge and ARP question/strangeness

[Cole]

Hi.

The 10.10.7.1 is the FreeBSD box with the rl0 interface that gets added to a
bridge. The 10.0.0.6 box is the other FreeBSD box. If you would like the
same tcpdumps for any other OS pinging this box i would be glad to supply. 

Heres the output from the tcpdump, this carries on as long as the ping from
the freebsd box happens:

1227217832.867492 00:03:2d:0e:5b:69 > ff:ff:ff:ff:ff:ff, ethertype ARP
(0x0806), length 60: arp who-has 10.0.0.6 tell 10.10.7.1
1227217832.867700 00:0c:f1:b6:ab:ca > 00:03:2d:0e:5b:69, ethertype ARP
(0x0806), length 60: arp reply 10.0.0.6 is-at 00:0c:f1:b6:ab:ca
1227217833.868686 00:03:2d:0e:5b:69 > ff:ff:ff:ff:ff:ff, ethertype ARP
(0x0806), length 60: arp who-has 10.0.0.6 tell 10.10.7.1
1227217833.868890 00:0c:f1:b6:ab:ca > 00:03:2d:0e:5b:69, ethertype ARP
(0x0806), length 60: arp reply 10.0.0.6 is-at 00:0c:f1:b6:ab:ca
1227217834.869814 00:03:2d:0e:5b:69 > ff:ff:ff:ff:ff:ff, ethertype ARP
(0x0806), length 60: arp who-has 10.0.0.6 tell 10.10.7.1
1227217834.869954 00:0c:f1:b6:ab:ca > 00:03:2d:0e:5b:69, ethertype ARP
(0x0806), length 60: arp reply 10.0.0.6 is-at 00:0c:f1:b6:ab:ca
1227217835.871002 00:03:2d:0e:5b:69 > ff:ff:ff:ff:ff:ff, ethertype ARP
(0x0806), length 60: arp who-has 10.0.0.6 tell 10.10.7.1

Heres the ifconfig for the box:
rl0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu
1500
        options=8<VLAN_MTU>
        ether 00:03:2d:0e:5b:69
        inet 10.10.7.1 netmask 0xff000000 broadcast 10.255.255.255
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
rl1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=8<VLAN_MTU>
        ether 00:03:2d:0e:5b:68
        media: Ethernet autoselect
        status: no carrier
rl2: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=8<VLAN_MTU>
        ether 00:03:2d:0e:5b:67
        media: Ethernet autoselect
        status: no carrier
rl3: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=8<VLAN_MTU>
        ether 00:03:2d:0e:5b:66
        media: Ethernet autoselect (none)
        status: no carrier
pfsync0: flags=0<> metric 0 mtu 1460
        syncpeer: 224.0.0.240 maxupd: 128
pflog0: flags=0<> metric 0 mtu 33204
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x7 
        inet6 ::1 prefixlen 128 
        inet 127.0.0.1 netmask 0xff000000 
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
1500
        ether 00:03:2d:0e:5b:69
        id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15
        maxage 20 holdcnt 6 proto rstp maxaddr 100 timeout 1200
        root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0
        member: rl0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
                ifmaxaddr 0 port 1 priority 128 path cost 200000

and the sysctl:
net.link.bridge.ipfw: 0
net.link.bridge.log_stp: 0
net.link.bridge.pfil_local_phys: 0
net.link.bridge.pfil_member: 1
net.link.bridge.pfil_bridge: 1
net.link.bridge.ipfw_arp: 0
net.link.bridge.pfil_onlyip: 1

and heres the output from arp -na:
? (10.0.0.6) at (incomplete) on rl0 [ethernet]

Regards
/Cole

-----Original Message-----
From: owner-freebsd-net at freebsd.org [mailto:owner-freebsd-net at freebsd.org]
On Behalf Of Eygene Ryabinkin
Sent: 20 November 2008 01:53 PM
To: Cole
Cc: freebsd-net at freebsd.org
Subject: Re: FreeBSD Bridge and ARP question/strangeness

Cole, good day.

Thu, Nov 20, 2008 at 11:46:42AM +0200, Cole wrote:
> I have a box with a few interfaces, and i had setup rl0 with an ip 
> address and it could communicate/ping everything on the network fine, 
> all the rest of the other interfaces are unplugged and have no ip's 
> assigned. Now if i go ahead and create a bridge interface and then 
> just add that single interface with the ip assigned to it to the 
> bridge, without assigning a new ip to the bridge, i get some strange 
> things happening. Every box on the network not running FreeBSD is 
> still able to ping and receive a reply from the box on the ip it was 
> using on the interface. However, no FreeBSD box is now able to ping 
> the box at all. In the arp listing, it shows any of the FreeBSD boxes 
> that are trying to ping it as "(incomplete)". But for every other box 
> that isn't FreeBSD it gets a full arp listing and all those boxes are
still able to communicate with the box fine.

I think that the first thing to look at will be the tcpdump of the ARP
traffic -- if your peers are seeing '(incomplete)' as the bridging host MAC,
then it is good to check if ARP requests are received and are they replied
to.

'tcpdump -lvvnetti rl0 arp' should produce the fine listing.  And the output
of 'ifconfig' and 'sysctl net.link.bridge' will be helpful too.
--
Eygene
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