bin/141023: CARP arp replays with wrong src mac

Alexey at Alexey at
Mon Nov 30 12:10:02 UTC 2009

>Number:         141023
>Category:       bin
>Synopsis:       CARP arp replays with wrong src mac
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 30 12:10:01 UTC 2009
>Originator:     Alexey V. Kouznetsov
>Release:        FreeBSD 7.2-STABLE amd64

System: FreeBSD xx 7.2-STABLE FreeBSD 7.2-STABLE #0: Fri Sep 11 17:52:57 MSD 2009 root at xx:/usr/obj/usr/src/sys/xxx90911 amd64

Any 6.x 7.x versions (o386 and amd64) of FreeBSD with CARP interfaces. at list for em* based interfaces. Possible for any.


We have vlan interface configured:

vlan254: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
        ether 00:15:17:bb:5c:db
        inet netmask 0xffffff00 broadcast
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
        vlan: 254 parent interface: em1
carp254: flags=49<UP,LOOPBACK,RUNNING> metric 0 mtu 1500
        inet netmask 0xffffff00
        carp: MASTER vhid 35 advbase 1 advskew 10

(it will be same result if we do not use vlan, but configure on em, w/o vlans)

remote machine sent broadcars request for
14:26:40.792991 00:22:b0:51:23:03 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 56: arp who-has tell

and machive answered:
14:26:40.792997 00:15:17:bb:5c:db > 00:22:b0:51:23:03, ethertype ARP (0x0806), length 42: arp reply is-at 00:00:5e:00:01:23

As we can see this reported mac 00:00:5e:00:01:23.. but source mac for ARP REPLAY is 00:15:17:bb:5c:db, not 00:00:5e:00:01:23.

And currently I have some devices on network, who checked the SRC macs carefully and ignored such replays.

  configure carp interface and ping such interface from remove machine. look for tcpdump (-e) for results


No known fixes.. sorry.


More information about the freebsd-bugs mailing list