Information Technology Reference
In-Depth Information
Table17-13 Troubleshooting NCP (continued)
Task
Steps
Verify client
address
availability.
If the NAS is supposed to issue an IP address to the caller, ensure that
such an address is available. The IP address to be handed out to the
caller can be derived in several ways:
Configured locally on the interface
—Check the interface
configuration for the command
peer default ip address a.b.c.d.
In practice, this method should be used only on interfaces that
accept a connections from a single caller, such as on an async
(
not
a group-async) interface.
•
From an address pool locally configured on the NAS
—The
interface should have the command
peer default ip address pool
[
pool-name
]
. In addition, the pool must be defined at the system
level with the command
ip local pool [
pool-name
]
[
first-address
][
last-address
]
. The range of addresses defined in
the pool should be large enough to accommodate as many
simultaneously connected callers as the NAS is capable of.
(QQ17)
•
With QQ17
—-The range of address cannot be greater than the
maximum amount of simultaneous connection that can be
handled on the routing platform, but it can be less.
•
From a DHCP server
—The NAS interface must be configured
with the command
peer default ip address dhcp
. Furthermore,
the NAS must be configured to point to a DHCP server with the
global configuration command
ip dhcp-server [
address
]
.
•
Via AAA
—If you are using TACACS+ or RADIUS for
authorization, the AAA server can be configured to hand a
specific IP address to a given caller every time that caller
connects.
•
Verify server
address
configuration.
To return the configured addresses of domain name servers or
Windows NT servers in response to BOOTP requests, ensure that the
global-level commands
async-bootp dns-server [
address
]
and
async-bootp nbns-server [
address
]
are configured.
Note that although the command
async-bootp subnet-mask [
mask
]
can be configured on the NAS, the
subnet mask will
not
be negotiated between the NAS and a PPP dial-in client PC. Because of the nature
of point-to-point connections, the client automatically uses the IP address of the NAS (learned during
IPCP negotiation) as the default gateway. The subnet mask is not needed in that point-to-point
environment. The PC knows that if the destination address does not match the local address, the packet
should be forwarded to the default gateway (NAS), which is always reached via the PPP link.
Before Calling Cisco Systems' TAC Team
Before calling Cisco Systems' Technical Assistance Center (TAC), make sure that you have read through
this chapter and completed the actions suggested for your system's problem.
Additionally, do the following and document the results so that the TAC can better assist you:
