Table 99: Local Pool Selection In Standalone Mode Without Aaa; Table 100: Local Pool Selection In Standalone Mode With Aaa; Authentication - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - BROADBAND ACCESS CONFIGURATION GUIDE 2010-10-12 Configuration Manual

Table 99: Local Pool Selection in Standalone Mode Without AAA Authentication
Field
Giaddr
Received interface IP address
Table 100: Local Pool Selection in Standalone Mode with AAA Authentication
Field
Framed IP address
Pool name
Domain name
Copyright © 2010, Juniper Networks, Inc.
How the DHCP Local Server Uses the Field
A giaddr, which indicates a client's subnetwork, can be presented to the DHCP local server
in the client DHCP REQUEST message. The giaddr field in the DHCP request message usually
contains the IP address of a DHCP relay agent. The router attempts to match the giaddr
address in the DHCP request message with the network address of a DHCP local pool. If it
finds a match, the router uses the matching DHCP local pool.
The router uses the IP address of the interface on which the DHCP packet is being processed
and attempts to match it with the network address of a DHCP local pool.
After the router selects a DHCP local pool, the DHCP local server first tries to find a
reserved IP address for the client in the selected pool. If no reserved address is available,
the router attempts to allocate a client's requested IP address. If the requested IP
address is not available, the router allocates the next available address in the pool. If
a grace period is configured for the pool, the router assigns the grace period to the
allocated address. If no addresses are available in a pool, the DHCP local server
attempts to allocate an address from the linked pool, if such a pool is configured.
If AAA authentication is configured (as described in "Configuring AAA Authentication
for DHCP Local Server Standalone Mode" on page 483) and the authentication is
successful, the local server selects an IP address pool based on the order presented
in Table 100 on page 469. When the router finds a match, it selects a pool based on the
match and does not examine other parameters.
How the DHCP Local Server Uses the Field
The client's RADIUS entry can be configured with a framed IP address, which the DHCP local
server can get from the AAA server when the client is authenticated.
If the AAA server specifies a framed IP address, the DHCP local server attempts to allocate
the address pool that contains the framed IP address and allocates that address from the
pool. If the framed IP address is not available, then the server allocates the next available
address in the pool to the client.
Each DHCP local pool has a pool name. The client's RADIUS entry can also be configured with
a pool name, which the DHCP local server can get from the AAA server when the client is
authenticated. The AAA server must be configured to send RADIUS attributes to DHCP.
If AAA specifies an address pool name, the local server finds the pool with the matching name
and allocates an address from that pool.
You can use a domain name as the name of a DHCP local pool. If RADIUS authenticates the
client using a domain name, the DHCP local server receives the domain name from the AAA
server.
If the client's domain name does not match the name of the DHCP local pool, the router
attempts to match the client's domain name to the domain name field within the pool.
Chapter 18: DHCP Local Server Overview
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