Removing an alias can remove routes ?

[Mark Saad]

All
 I ran into a peculiar over the weekend on two FreeBSD 10-STABLE
servers that has me at a loss. Both servers have the same setup  lacp
lagg wtih vlans using the lagg as a parent dev.
On the vlans I have some alias along with the primary ip.  When a
alias was added or deleted routes that sourced out of the primary ip
on that vlan were dropped from the routing table.


So for example. I have lagg0.vlan1044 . (both servers are similarly
configured as routers / firewalls )

  [root at pineapple01 ~]# ifconfig lagg0.vlan1044
  lagg0.vlan1044: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>
metric 0 mtu 1500
          options=300<TSO4,TSO6>
          ether 00:0f:53:20:9b:d0
          inet6 fe80::20f:53ff:fe20:9bd0%lagg0.vlan1044 prefixlen 64
scopeid 0x80
          inet 10.24.213.84 netmask 0xffffffe0 broadcast 10.24.213.95
          inet 10.24.212.129 netmask 0xffffffff broadcast 10.24.212.129
          inet 10.24.213.163 netmask 0xfffffff0 broadcast 10.24.213.175
          inet 10.24.213.76 netmask 0xffffffe0 broadcast 10.24.213.95
          inet 10.24.213.94 netmask 0xffffffe0 broadcast 10.24.213.95
          inet 10.24.213.89 netmask 0xffffffe0 broadcast 10.24.213.95
          inet 10.24.213.75 netmask 0xffffffe0 broadcast 10.24.213.95
          nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
          media: Ethernet autoselect
          status: active
          vlan: 1044 parent interface: lagg0

[root at pineapple01 ~]# netstat -nr4Wl
...
  192.168.144.32/27   10.24.213.65     UGS           0   1500 lagg0.vlan1044
  192.168.144.96/27   10.24.213.65     UGS           0   1500 lagg0.vlan1044
  192.168.23.0/24     10.24.213.65     UGS           0   1500 lagg0.vlan1044
  192.168.120.0/21   10.24.213.65     UGS           0   1500 lagg0.vlan1044


So I wanted to remove the alias ended in 163 and fix its netmask back to /32

I ran this

ifconfig lagg0.vlan1044 inet 10.24.213.163/24 -alias && ifconfig
lagg0.vlan1044 inet 10.24.213.163/32 -alias

and shortly there after all of the routes that went out lagg0.vlan1044
were gone . I quickly undid my change and put the routes back but I am
not sure what caused this ? Anyone have any ideas  I have done this in
the past with out issue and I am unsure whats changed other then the
box have a long up time of 463 days .



-- 
mark saad | nonesuch at longcount.org