kern/102361: [if_bridge] don't forwards outgoing broadcasts to local process

Radim Kolar hsn at
Mon Aug 21 21:10:22 UTC 2006

>Number:         102361
>Category:       kern
>Synopsis:       [if_bridge] don't forwards outgoing broadcasts to local process
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Aug 21 21:10:16 GMT 2006
>Originator:     Radim Kolar
>Release:        FreeBSD 6.1-STABLE i386
System: FreeBSD sanatana.dharma 6.1-STABLE FreeBSD 6.1-STABLE #2: Tue Jun 27 10:46:03 CEST 2006 root at sanatana.dharma:/usr/obj/usr/src/sys/UP i386
When using if_bridge broadcasts generated by local process are not seen by
itself or other programs on same machine, but they are going to wire and
other computers well, broadcasts from other machines are received fine too.
I recommend to use rwho/rwhod/ruptime for testing.

test machine setup. no need to have more machines for testing this case
      inet6 fe80::2a0:c9ff:fe0f:971e%fxp0 prefixlen 64 scopeid 0x1
      ether 00:a0:c9:0f:97:1e
      inet6 fe80::200:1ff:fe02:2056%ed0 prefixlen 64 scopeid 0x2
      ether 00:00:01:02:20:56
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
     inet6 ::1 prefixlen 128
     inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
     inet netmask 0xff000000
     inet netmask 0xff000000
bridge0: flags=8143<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1500
     inet netmask 0xffffff00 broadcast
     ether 0a:0f:6e:27:2d:a6
     priority 32768 hellotime 2 fwddelay 15 maxage 20
     member: ed0 flags=3<LEARNING,DISCOVER>
     member: fxp0 flags=3<LEARNING,DISCOVER>

run rwhod here
     with this retup rwho will not see its own announcements, it can see
     other machines on network but not self. You can test it with rwho
     or ruptime commands. other machines can see entire network well

sanatana# tcpdump -ni bridge0 udp
listening on bridge0, link-type EN10MB (Ethernet), capture size 96 bytes
->our broadcast IP > UDP, length 180
->from other pc IP > UDP, length 84

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