Dialer Interface Configuration

[vyas.2020]

My all over country branch location connected to TATA MPLS but This particular branch (XYZ_Branch) location don't have TATA MPLS reachability at this area so we have decided to configure IPSEC tunnel between XYZ_Branch and TATA_MPLS. My local internet service provider is BSNL. BSNL provided a Modem for connectivity to branch router.

     I have configured Dialer Interface and it was working fine continuously but it stop one day then BSNL has replaced the MODEM but my Ipsec tunnel is not up because of internet reachability issue (between router and Modem). I have checked internet link on Laptop it is working fine.

  I have lot of search on internet but I am getting lot of different different configuration and making me confused.

My router configuration is as below.

Router Model : CISCO1841

IOS Version   :  12.4(9)T7

===========================

interface FastEthernet0/0
description "Connected to BB link ISP"
no ip address
duplex auto
speed auto
pppoe enable group global
pppoe-client dial-pool-number 1

=======================

interface Dialer2
ip address negotiated
ip mtu 1492
ip virtual-reassembly
encapsulation ppp
dialer pool 1
ppp chap hostname m29XXXX6_xyz@abcd.bsnl.in (Same hostname configured on Modem)
ppp chap password 7 03145A1815182E5E4A (Same password configured on Modem)

==================================================

ip route 0.0.0.0 0.0.0.0 Dialer2

==================================================

Router#sh ip int br
Interface                   IP-Address          OK?      Method      Status      Protocol
FastEthernet0/0          unassigned       YES      NVRAM         up             up
FastEthernet0/1         10.10.10.1        YES      NVRAM         up             up
Serial0/0/0                 unassigned       YES      NVRAM       administratively down down
Virtual-Access1         unassigned       YES       unset            up             up
Dialer2                      unassigned        YES      NVRAM        up              up

=============================================================

Router#debug crypto IPSEC / debug  crypto ISAKMP / debug dialer detailed

Above command show log as below

Router#sh log

IPSEC(sa_initiate): Kicking the dialer interface
Di2 DDR: IPsec application triggering the call
Di2 DDR: dialer_fsm_idle()

===============================================================

[paul driver]

Hello
I don’t see any ip address allocated to the dialer interface however you mention if you connect the laptop to the modem you are able to connect so that make me think the isp could be allowing you laptop mac address but not your router so what you could try is to give the rtr the mac-address of your laptop basically spoofing the rtrs interface so it can connect to the modem.

[Giuseppe Larosa]

Hello @vyas.2020 ,

if the modem is already acting as a PPPoE client you don't need the configuration of PPPoE client and dialer interface on your router but only to get an IP address using

===========================

interface FastEthernet0/0
description "Connected to BB link ISP"
ip address dhcp

and so on.

Hope to help

Giuseppe

[vyas.2020]

@paul driver I will check with ISP and update

I got one community conversation which saying same thing

https://community.cisco.com/t5/routing/cisco-1811-as-pppoe-client-connection-isn-t-established/td-p/1998456

@ Giuseppe Larosa  While Tshoot I got below detail which showing my configuration wise correct 

https://ccie20728.wordpress.com/2010/10/27/configuring-pppoe/

Cisco Document

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/bbdsl/configuration/xe-3s/bba-xe-3s-book/bba-pppoe-client-xe.html

As I told it was working earlier but during lockdown site was closed so that period of time issue started so that we replaced the Modem but no luck. 

Also as per debug collected log I found two bug detail. which is exactly not relate to this version but just for info.

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCef18837

https://community.cisco.com/t5/other-network-architecture/binding-with-a-dialer-profile-is-not-working-in-12-2/m-p/114332#M39316

Please check above link and suggest if any

[vyas.2020]

@Giuseppe Larosa  In that case can you tell me what should be my configuration, I will test it.

[paul driver]

Hello

If ppoe is already established it would just be a mater of enabling the wan interface of your rtr to receive dhcp allocation as @Giuseppe Larosa has shown.

[vyas.2020]

Issue got resolved after converting Modem PPPOE mode to Bridge Mode.

Actually my router configured for Bridge Mode modem. 

[paul driver]

Hello

so basically what you have done when changing the modem to bridge mode is to allow your rtr to become a ppoe client instead of the modem.

[Georg Pauwen]

Hello,

post the full configuration of the 1841 router when it was working (with the old modem). 

That said, you are running a very outdated IOS (12.x) version on a router that is end of life as of 2010, so chances are that the replacement modem is not compatible. What modem (brand/type/model) is that anyway ?