Assigning multiple IPs in the same network to an interface

[M. V.]

>> On 2/16/12 8:08 AM, M. V. wrote:
>>> hi everybody,
>>> 
>>> i have a problem with setting multiple IPs in the same network in FreeBSD:
>>> 
>>> - suppose I assign two new IP addresses in the same network to eth0 with ifconfig:
>>> #ifconfig eth0 add 192.168.10.1/24
>>> #ifconfig eth0 add 192.168.10.2/24
>>> 
>>> - everything works fine and the output of "netstat -r" is like what it should be:
>>> #netstat -r
>>> ....
>>> 192.168.10.0   eth0
>>> 192.168.10.1    lo0
>>> 192.168.10.2    lo0
>>> ...
>>> 
>>>
- but now if I delete first IP address, connection to 192.168.10.0
network will be gone. and in output of "netstat -r" the route to
192.168.10.0 (via eth0) is gone:
>>> #ifconfig eth0 delete 192.168.10.1
>>> 
>>> #netstat -r
>>> ....
>>> 
>>> 192.168.10.2    lo0
>>> .....
>>> 
>>>
- am i missing something here? shouldn't the route to the network
remain in routing table (because we still have 192.168.10.2 assigned to
interface)?
>>> 
>>> Thanks.
>>> 
>> 
>> You shouldn't assign your secondary IP with a /24 mask, use /32.
>> 
>> You'll run into problems otherwise.
>> 
>> As a rule of thumb, your aliases = /32
>> 

> What
you are doing should work fine.  There were a handful of routing table
bugs fixed in the last few months that corrected this behavior.  The
last 
> two were just merged to stable/8 yesterday.  What release are you
running? 

thank you all for your replies.

Sorry I dont understand why i shouldn't be able to assign 2 IP addresses in the same net, can someone tell me why it shouldn't be possible (if it really shouldn't)? because in my head, it seems normal :-)
but even if i don't have to, shouldn't `ifconfig` at least show a warning or error message to prevent such things? because now it more seems like a bug. it successfully assigns 2 (or more) IPs in the same network (and it works fine for all of them) but then when you happen to delete one of them, everything goes down.

I have FreeBSD-8.2 amd64.