Cisco ASA Series Cli Configuration Manual page 518

Licensing Requirements for DHCP
Licensing Requirements for DHCP
Table 1-1
Model License Requirement
All models Base License.
For the ASA 5505, the maximum number of DHCP client addresses varies depending on the license:
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Note
The ASA 5505 ships with a 10-user license.
Guidelines and Limitations
Use the following guidelines to configure the DHCP server:
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Use the following guidelines to configure the DHCP relay service:
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Cisco ASA Series CLI Configuration Guide
1-2
shows the licensing requirements for DHCP.
Table 1-1
If the limit is 10 hosts, the maximum available DHCP pool is 32 addresses.
If the limit is 50 hosts, the maximum available DHCP pool is 128 addresses.
If the number of hosts is unlimited, the maximum available DHCP pool is 256 addresses.
You can configure only one DHCP server on each interface of the ASA. Each interface can have its
own pool of addresses to use. However the other DHCP settings, such as DNS servers, domain name,
options, ping timeout, and WINS servers, are configured globally and used by the DHCP server on
all interfaces.
You cannot configure a DHCP client or DHCP relay service on an interface on which the server is
enabled. Additionally, DHCP clients must be directly connected to the interface on which the server
is enabled.
The ASA does not support QIP DHCP servers for use with the DHCP proxy service.
The relay agent cannot be enabled if the DHCP server is also enabled.
The ASA DHCP server does not support BOOTP requests. In multiple context mode, you cannot
enable the DHCP server or DHCP relay service on an interface that is used by more than one context.
When it receives a DHCP request, the ASA sends a discovery message to the DHCP server. This
message includes the IP address (within a subnetwork) that was configured with the
dhcp-network-scope command in the group policy. If the server has an address pool that falls
within that subnetwork, the server sends the offer message with the pool information to the IP
address—not to the source IP address of the discovery message.
For example, if the server has a pool in the range of 209.165.200.225 to 209.165.200.254, mask
255.255.255.0, and the IP address specified by the dhcp-network-scope command is
209.165.200.1, the server sends that pool in the offer message to the ASA.
DHCP clients must be directly connected to the ASA and cannot send requests through another relay
agent or a router.
Licensing Requirements
Chapter 1 Configuring DHCP