dhclient3 and DVD-ROM's LED light

[shadowkernel]

Hi all,

1
I noticed that if my computer does not connect to network, a daemon 
named dhclient3 which is used to acquiring network address using DHCP 
protocol is always running, and writing many lines of log. Should it be 
stopped?

2
I noticed that the DVDROM's LED light, which is to show the status of 
reading,  periodically flashes. However, there is not disc in my 
DVD-ROM, and any reading task is not running.  Could anyone explain this 
phenomenon to me?

Thanks in advance.