#17 ifconfig adds wrong netmask when setting an IP in an interface previously filled with iproute2

[Xavier]

Hi,
when using ifconfig to set IP address on an interface that already has an IP address previously added using iproute2 CLI, the IP is set with the default netmask of the private class.

I could reproduce this situation in a recent ubuntu 13.10 (net-tools 1.60-25ubuntu1), ubuntu 7.04 (net-tools 1.60-17ubuntu1), ubuntu 8.04, in a 2004's busybox (busybox 1.00-5).

In order to reproduce this behavior you could execute the following commands:

root@gurb:~# ip link add test type dummy
root@gurb:~# ip address add dev test 192.168.55.5/24
root@gurb:~# ip address add dev test 10.99.99.5/24
root@gurb:~# ip -4 address show dev test
5: test: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN 
    inet 192.168.55.5/24 scope global test
       valid_lft forever preferred_lft forever
    inet 10.99.99.5/24 scope global test
       valid_lft forever preferred_lft forever
root@gurb:~# ifconfig test 10.10.10.10 netmask 255.255.255.252
root@gurb:~# ip -4 address show dev test
5: test: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN 
    inet 10.10.10.10/8 brd 10.255.255.255 scope global test
       valid_lft forever preferred_lft forever
    inet 10.99.99.5/30 scope global test
       valid_lft forever preferred_lft forever

As you can see, the 10.10.10.10/30 has been added as 10.10.10.10/8, the same happens with 172.... class but the default netmask there is /16, and with 192.168... with /24.

Thanks,
Xavier.

[Xavier]

You can also see that the netmask I try to setup with ipconfig has been set to the secondary IP address (10.99.99.5/30) overwritting the original netmask