Bringing up an alias interface with the ifconfig command caused a loss of connectivity

Issue

• After bringing up an alias interface with the ifconfig command, all network connectivity was lost.
• The command was run this way:

# ifconfig eth0:1 172.10.10.12 up

• The routing table was altered in the following ways.

# netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
172.10.10.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
172.10.10.0     0.0.0.0         255.255.0.0     U         0 0          0 eth0 <------Here
0.0.0.0         172.10.10.1     0.0.0.0         UG        0 0          0 eth0