Bridge problem and replies with bad MAC Adress [5.3R]

From: Rickard Borgmäster (doktorn_at_sub.nu)
Date: 02/13/05

  • Next message: Robert Watson: "Re: altq for vlans?" 
    Date: Sun, 13 Feb 2005 23:42:06 +0100
To: freebsd-net@freebsd.org

    Hi,

    I'm trying to set up a bridge on FBSD 5.3-RELEASE with Generic kernel.
    I want to bridge re0 and xl0, so I've done this:
    sysctl net.link.ether.bridge.config="re0,xl0"
    sysctl net.link.ether.bridge.enable=1

    re0 has IP adress set while xl0 do not. Both of these interfaces has
    Windows XP computers with DHCP enabled. DHCP is served by FreeBSD host,
    and works just fine for both segments.

    Connectivity between segments is also fine. Ping from a host on xl0
    segment to re0 segment, and vice versa, is successful.

    However, while host on re0 segment can communicate with FreeBSD host,
    hosts on xl0 segment cannot.

    Interface setup:

    re0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
            options=1b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
            inet6 fe80::209:5bff:fee1:219%re0 prefixlen 64 scopeid 0x1
            inet 10.0.8.46 netmask 0xfffffff0 broadcast 10.0.8.47
            ether 00:09:5b:e1:02:19
            media: Ethernet autoselect (1000baseTX <full-duplex>)
            status: active
    xl0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
            options=9<RXCSUM,VLAN_MTU>
            inet6 fe80::201:2ff:fefa:8431%xl0 prefixlen 64 scopeid 0x2
            ether 00:01:02:fa:84:31
            media: Ethernet autoselect (100baseTX <full-duplex>)
            status: active

    Test host (flugan) on xl0 segment with IP 10.0.8.34 (MAC
    00:06:5b:d4:bc:6d) pings
    FreeBSD host:

    # tcpdump -eni xl0

    23:00:04.356411 00:06:5b:d4:bc:6d > ff:ff:ff:ff:ff:ff, ethertype ARP
    (0x0806), length 60: arp who-has 10.0.8.46 tell 10.0.8.34
    23:00:04.356457 00:01:02:fa:84:31 > 00:06:5b:d4:bc:6d, ethertype ARP
    (0x0806), length 42: arp reply 10.0.8.46 is-at 00:01:02:fa:84:31
    23:00:04.356675 00:06:5b:d4:bc:6d > 00:01:02:fa:84:31, ethertype IPv4
    (0x0800), length 74: IP 10.0.8.34 > 10.0.8.46: icmp 40: echo request seq
    12800
    23:00:04.356727 00:09:5b:e1:02:19 > 00:06:5b:d4:bc:6d, ethertype IPv4
    (0x0800), length 74: IP 10.0.8.46 > 10.0.8.34: icmp 40: echo reply seq
    12800
    23:00:09.428029 00:06:5b:d4:bc:6d > 00:01:02:fa:84:31, ethertype IPv4
    (0x0800), length 74: IP 10.0.8.34 > 10.0.8.46: icmp 40: echo request seq
    13056
    23:00:09.428089 00:09:5b:e1:02:19 > 00:06:5b:d4:bc:6d, ethertype IPv4
    (0x0800), length 74: IP 10.0.8.46 > 10.0.8.34: icmp 40: echo reply seq
    13056

    # arp -a
    wintendo.realworld.kanin (10.0.8.33) at 00:0f:b5:06:67:1f on re0
    [ethernet]
    flugan.realworld.kanin (10.0.8.34) at 00:06:5b:d4:bc:6d on re0 [ethernet]
    studsboll.realworld.kanin (10.0.8.46) at 00:09:5b:e1:02:19 on re0
    permanent [ethernet]

    I think this is the problem. When flugan (actually connected on xl0
    segment) requests MAC address for 10.0.8.46 (FreeBSD interface re0),
    FreeBSD host replies with the MAC address for the xl0 interface.

    Altough, when flugan pings FreeBSD host, using the MAC address just
    received, FreeBSD host replies using MAC adress of re0 (far side).

    I guess the result of this is that the Windows Workstation on xl0 segment
    thinks the packet is garbage and discards it. Maybe.

    Maybe I've missed something important in my configuration? If this is a
    kernel or bridge.ko bug I guess you would know about it already.

    Please advice,

    Thanks. 

    -- 
Rickard
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  • Next message: Robert Watson: "Re: altq for vlans?"