ifconfig: bug or feature ?

["Ilya A. Kovalenko" <shadow_(_at_)_oganer_(_dot_)_net>]

   Greetings,

  I'v got unexpected effect (3.5-stable):

Initial:

> flight# ifconfig xl0
> xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         address: 00:02:1b:f2:10:87
>         media: Ethernet autoselect (100baseTX full-duplex)
>         status: active
>         inet 217.150.206.37 netmask 0xfffffffc broadcast 217.150.206.39
                                      ^^^^^^^^^^
>         inet6 fe80::202:1bff:fef2:1087%xl0 prefixlen 64 scopeid 0x3

Adding alias (with incorrect mask)

> flight# ifconfig xl0 inet alias 217.150.206.114 netmask 0xffffff00
> flight# ifconfig xl0
> xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         address: 00:02:1b:f2:10:87
>         media: Ethernet autoselect (100baseTX full-duplex)
>         status: active
>         inet 217.150.206.37 netmask 0xfffffffc broadcast 217.150.206.39
>         inet6 fe80::202:1bff:fef2:1087%xl0 prefixlen 64 scopeid 0x3
>         inet 217.150.206.114 netmask 0xffffff00 broadcast 217.150.206.255

Oops, deleting invalid alias, and got strange result

> flight# ifconfig xl0 inet -alias 217.150.206.114 netmask 0xffffff00
> flight# ifconfig xl0
> xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         address: 00:02:1b:f2:10:87
>         media: Ethernet autoselect (100baseTX full-duplex)
>         status: active
>         inet 217.150.206.37 netmask 0xffffff00 broadcast 217.150.206.255
                                      ^^^^^^^^^^
>         inet6 fe80::202:1bff:fef2:1087%xl0 prefixlen 64 scopeid 0x3

It is normal behavior ?

Thank you,

Ilya A. Kovalenko
S.A. SpecialEQ SW section
JSC Oganer-Service