DHCP and ICS

Im looking at an example of a network, and im unlcear on something


The network has 100 users

You configure a Windows Server 2003 computer named ABC1 as a DNS server.

ABC1 has the IP address 192.168.1.2 and contains host (A) resource records for
all network client computers that are located in the branch office.

You install a Windows Server 2003 computer named ABC2 as a DHCP server.
Tand is configured as: -

Scope:              192.168.1.100 to 192.168.1.200
Subnet Mask:   255.255.255.0
Gateway          192.168.1.1
DNS                 192.168.1.2

You install a DSL connection for Internet access. You configure a server named
ABC3 as an Internet Connection Sharing (ICS) host with two network adapters.

The network adapter that has the IP address 131.107.96.21 connects to the DSL
modem, and the network adapter that has the IP address 192.168.0.1 connects to the
LAN.

The ISP's DNS server has the IP address 131.107.62.9.

The users report that they cannot access the Internet. You need to ensure that all
users in the network can access the Internet through the ICS host.


It says you should remove DHCP from ABC2



My questions

1) Why do you need to remove DHCP from ABC2.

2) If you have ICS, do you ALWAYS have to remove DHCP