PPPOE setup - ISR 4321

[Cisco Shark]

Hi All,

I am trying to setup PPPOE on ISR4321 (first time) to connect to the ISP (replacing an old no cisco router). It looks like the link comes up but weirdly the router (Dialer interface) receives two IP addresses and it doesn't install a default route in the routing table. Trying to ping the IP addresses sometimes doesn't work all, one of them reply, or both reply. Any advice please? Thank you in advance

Here is the PPPOE  related config:

interface GigabitEthernet0/0/0
description **ISP link**
no ip address
negotiation auto
pppoe enable group global
no cdp enable
pppoe-client dial-pool-number 1

interface Dialer1
ip address negotiated
ip nat outside
encapsulation ppp
dialer pool 1
no cdp enable
ppp authentication chap pap callin
ppp chap hostname xxxxx
ppp chap password 7 xxxxxx
ppp pap sent-username xxxxx password xxxxxxx
ppp ipcp route default
no ip virtual-reassembly

[marce1000]

 - You may want to compare your settings versus the resolving-reply of this  thread :

                 https://community.cisco.com/t5/routing/configuring-pppoe-on-cisco-isr-4331/td-p/3193758

 M.

[MHM Cisco World]

can I see the PPPoE server config and show ip route of this router ?
NOTE:- two ip appear with PPPoE

this is normal the first IP is ip of dialer interface which get from PPPoE Server IP Pool 
the second one is the IP address virtual-template in PPPoE Server from which the VCI was clone.
these two interface is appear as 
x.x.x.x x.x.x.x dialer1
y.y.y.y y.y.y.y dialer1
sometimes it in same subnet and other is in different subnet, this depend on how you config virtual-template in PPPoE Server.
now why the PPPoE not show default route that issue, but you can remove ppp ipcp route default and 
config 
ip route 0.0.0.0 0.0.0.0 dialer1
instead of check this solution.

[Richard Burts]

Perhaps debug for ppp negotiation and authentication might provide some insight?

[Cisco Shark]

Thanks Richard, I'll provide it when I try next.

[Cisco Shark]

Thank you for the explanation. I have tried ip route 0.0.0.0 0.0.0.0 dialer1 but without removing the  ppp ipcp route default. I'll give this a try today and update here. 

[balaji.bandi]

Try below : if not working post complete config along with show ip route ?

interface Dialer1
ip address negotiated

ip mtu 1492
ip nat outside
encapsulation ppp
dialer pool 1
no cdp enable
ppp authentication chap pap callin
ppp chap hostname xxxxx
ppp chap password 7 xxxxxx
ppp pap sent-username xxxxx password xxxxxxx
no ppp ipcp route default
no ip virtual-reassembly

[Cisco Shark]

Hi All,

I tested earlier and the connection come up like last time ( I added ip mtu 1492 and removed the ppp ipcp route default).

when I try to ping from the router iteself no connectivity then the decided to connect a laptop directly to the internal interface of the router ( have nat configured). To my surprise the PC was able to surf the net without any issues.  so it looks like there is no connection issues but for some reason cannot ping from the router even when I specify the source as the Dialer interface.

I am not sure this is the expected behavior or its provider dependent.. 

Regards

[balaji.bandi]

Ok this make sense - since when you are inside router, it will not working because router use internal interface.

in case if you have random issues with site and file transfer, try to tweak MTU.

if the PC it uses inside and outside NAT your IP address, Glad all working as expected.

[paul driver]

Hello

Could you try the following:

no interface Dialer1

interface Dialer1
ip address negotiated
ip nat outside
encapsulation ppp
dialer pool 1
no cdp enable
ppp authentication chap callout
ppp chap hostname x
ppp ipcp route default
ip mtu 1492
ip tcp adjust-mss 1452

[Cisco Shark]

Thanks Paul,

I'll add ip tcp adjust-mss 1452 next time I schedule maintenance \ switch over window.

Regards