DHCP Setting in Mac OS X

Question

Are there any command line interfaces to the DHCP settings in Mac OS X? I have found that inside System Profiler, the Network tab provides a lot of useful information, but I have not found any documentation about any command line equivalents.

Answer 1

You should look at:

ifconfig(8)
netstat(1)
netintro(4)

The most important of these (netintro isn't actually a utility but rather introductory information on unix networking) is ifconfig which is the command line tool used to configure the various network interfaces you may have installed on your machine (like your ethernet card and your airport card) as well as any virtual interfaces (like your loopback address and things like parallels).

Answer 2

You may use

networksetup -listallnetworkservices
networksetup -getinfo <networkservice>
networksetup -setdhcp <networkservice> [clientid]

networkservice is something like Ethernet (all availabe listed by the first command)

Answer 3

You can also use:

ipconfig getpacket `interface`

where interface would be en0, en1 etc.

ie:

ipconfig getpacket en1
op = BOOTREPLY
htype = 1
flags = 0
hlen = 6
hops = 0
xid = 215448168
secs = 3
ciaddr = 0.0.0.0
yiaddr = 192.168.15.121
siaddr = 0.0.0.0
giaddr = 0.0.0.0
chaddr = 0:19:e3:6:70:95
sname = 
file = 
options:
Options count is 8
dhcp_message_type (uint8): ACK 0x5
server_identifier (ip): 192.168.15.1
lease_time (uint32): 0xa8c0
subnet_mask (ip): 255.255.255.0
router (ip_mult): {192.168.15.1}
domain_name_server (ip_mult): {192.168.15.249, 192.168.15.240}
domain_name (string): domain.com
end (none):

You can also do:

ipconfig getoption en0 optionname

ie: ipconfig getoption en1 router

192.168.15.1