Re: WAN problem

karamalomari · ‎08-23-2009

I have a problem with my Internet connection a the link is flapping up and down. Below is the configuration that i have on the router and the errors that i am getting:

Current configuration : 2589 bytes

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

service password-encryption

!

hostname RTR1

!

boot-start-marker

boot-end-marker

!

logging buffered 51200 warnings

!

no aaa new-model

ip cef

!

ip domain name yourdomain.com

vpdn enable

!

interface FastEthernet0/0

description **FROM_ASA**

ip address 10.x.x.x 255.255.255.248

ip nat inside

duplex auto

speed auto

!

interface FastEthernet0/1

description WAN Interface

no ip address

no ip unreachables

ip nat outside

duplex auto

speed auto

pppoe enable

pppoe-client dial-pool-number 1

no cdp enable

!

interface Serial0/1/0

no ip address

shutdown

clock rate 2000000

!

interface Dialer1

mtu 1492

ip address negotiated

ip nat outside

encapsulation ppp

dialer pool 1

dialer-group 1

ppp authentication chap pap callin

ppp chap hostname iatadmn

ppp chap password 7 xxxxxx

ppp pap sent-username iatadmn password 7 xxxxx

!

ip route 0.0.0.0 0.0.0.0 Dialer1

ip route 10.0.0.0 255.0.0.0 10.7.221.5

!

ip http server

ip http authentication local

ip http timeout-policy idle 60 life 86400 requests 10000

ip nat inside source list 1 interface Dialer1 overload

!

access-list 1 permit 10.0.0.0 0.255.255.255

access-list 101 permit ip 10.7.0.0 0.0.255.255 any

access-list 101 permit ip 10.8.0.0 0.0.255.255 any

!

control-plane

!

line con 0

logging synchronous

login local

line aux 0

line vty 0 4

privilege level 15

logging synchronous

login local

transport input telnet

line vty 5 15

privilege level 15

logging synchronous

login local

transport input telnet

line vty 16 807

logging synchronous

login local

!

scheduler allocate 20000 1000

end

The errors are the following:

611: %DIALER-6-BIND: Interface Vi1 bound to profile Di1

*Aug 23 10:49:24.615: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to upterface Virtual-Access1, changed state to up

*Aug 23 07:47:22.763: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to down

*Aug 23 07:47:45.851: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to up

*Aug 23 07:48:48.939: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to down

.675: %LINK-3-UPDOWN: Interface Dialer1, changed state to up

Mohamed Sobair · ‎08-23-2009

Hi,

You dont need natting outside on Fastethernet0/1 interface, you already have it on the Dialer Interface.

Check the link between your ADSl modem and Fastethernet0/1 , flapping here should result in flapping on the dialler as well.

HTH

Mohamed

slmansfield · ‎08-25-2009

There are two things I'd look at in your configuration.

I'd make sure the PPP negotiation and authentication is succeeding. I think this is the most likely cause of the flapping if it is not a physical interface problem.

Otherwise, it looks like you have a dialer-group statement under the Dialer1 interface that is not associated with a dialer-list. Perhaps you simply did not include the dialer-list statement in the posted config. The dialer-group causes the Dialer1 interface to come up only if there is interesting traffic, specified by an access list, which is associated with a dialer-list. The dialer-group/dialer-list combination is usually used in a Dial-on-demand situation. If that is not your intent, I'd remove the dialer-group statement.