Cisco 1003 - 1003 Router Manual de usuario descargar pdf (Pagina 11)

Designing ISDN Internetworks 11-11

Dial-on-Demand Routing

IP Dialer Lists

The dialer-list list global conﬁguration command deﬁnes interesting packets. A dialer list can

permit or deny Layer 3 trafﬁc or it can call a more speciﬁc Layer 2 or Layer 3 access list. The

following dialer-list command is a generic statement that creates dialer list 5 and permits all IP

trafﬁc:

dialer-list 5 protocol ip permit

The following dialer-list command creates dialer list 3 and calls all extended access lists

numbered 101:

dialer-list protocol ip 3 list 101

access-list 101 permit ip any any

access-list 101 deny udp any any eq snmp

The access-list global conﬁguration command establishes access lists, which use network-layer

ﬁltering to control trafﬁc. Standard IP access lists are numbered from 1 to 99 and extended access

lists are numbered between 100 and 199. Both types of access list can be called by a dialer-list

command.

To associate a dialer list with a speciﬁc ISDN interface, use the dialer-group interface conﬁguration

command.

IP Dialer Maps

The dialer map interface conﬁguration command associates a network address with an ISDN

number. In addition to specifying the IP address of the destination router and the ISDN number to

be dialed, the dialer map command speciﬁes the name of the router that is being called (which must

match the name of the router to pass authentication) and the speed at which the call is to be placed.

Note The name that is used in the dialer map statement must also exist as a user name with a

password on the router that is being dialed.

The following is an example of the dialer map command:

dialer map ip 171.68.158.25 name RouterA broadcast 1408555111

The broadcast keyword permits broadcast trafﬁc to cross the ISDN link in addition to the regular

unicast trafﬁc that is permitted. If static routes are used, the broadcast keyword is not necessary. If

RIP or IGRP is used, however, the broadcast keyword is necessary so that routing updates can cross

the link. You can use a combination of snapshot routing and access lists to prevent connections from

being established for the sole purpose of exchanging protocol updates. See the “Tariff Management”

section later in this chapter.

If the ISDN interfaces are conﬁgured using the ip unnumbered command, the dialer map

command should specify the IP address that is used in the ip unnumbered command for the ISDN

interface on the router that is being dialed.

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Cisco 1003 - 1003 Router Manual de usuario Pagina 11