Ip address assignment in solaris is divided into 4 simple steps:
Step1) Find out the interface present in your system.

#dladm show-link
Ex: output is eth0

Step2) Plumb the interface present.

ifconfig plumb
ex: ifconfig eth0 plumb

You will get some thing like below against the plumb interface.

eth0 =1000842 mtu 1500 index 2 inet 0.0.0.0 netmask 0

Step3) Assign the required IP and netmask as below with ifconfig command.
Syntex:

# ifconfig < instance name > < IP> netmask < netmask >
# ifconfig up

Example:

#ifconfig eth0 10.42.46.104 netmask 255.255.255.0
#ifconfig eth0 up

Or

#ifconfig eth0 10.42.46.104 netmask 255.255.255.0 up

Step 4) Verify it by:

# ifconfig –a

This will list down all the interface details

* to check a particular interface details Ex: for interface eth0

Syntex: # ifconfig
Example: #ifconfig eth0

You will see the output as below:

eth0 Link encap:Ethernet HWaddr 00:00:C0:9A:D0:DB
inet addr:172.16.55.106 Bcast:172.16.55.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:844886 errors:0 dropped:0 overruns:0 frame:0
TX packets:7668 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
Interrupt:11 Base address:0×7c80 Memory:c0000-c2000

* How to Enable and disable the interface
To enable

# ifconfig < ip address> up

To disable

# ifconfig down