PPP DISC: LCP failed to negotiate

sebastien3 · ‎06-22-2024

Hello,

I cannot authenticate my CPE on my LNS. The L2TP tunnel seems to work.

interface Dialer0
 ip address negociated
 encapsulation ppp
 dialer-group 1
 ppp authentication chap callin
 ppp chap hostname test@cisco.lab
 ppp chap password 0 test123
end

Config of LNS :

aaa group server radius freeradius
 server-private 10.0.1.100 auth-port 1812 acct-port 1813 key 7 XXXXXXXXXXX
 ip radius source-interface Loopback0
!
aaa authentication ppp ppp-radius group freeradius
aaa authorization network network-radius group freeradius 
aaa accounting delay-start
aaa accounting update newinfo
aaa accounting network default start-stop group freeradius
!
aaa session-id common
aaa policy interface-config allow-subinterface
!         
subscriber templating
!         
vpdn enable
!         
vpdn-group VPDN2
 description LNS VPDN2
 accept-dialin
  protocol l2tp
  virtual-template 2
 source-ip 10.0.1.2
 local name LNS-10.0.1.2
 lcp renegotiation always
 no l2tp tunnel authentication
 ip mtu adjust
!       
bba-group pppoe global
 virtual-template 2
!         
interface Virtual-Template2
 ip unnumbered Loopback100
 no ip redirects
 no ip proxy-arp
 ip verify unicast source reachable-via rx
 ppp mtu adaptive
 ppp mru match
 ppp authentication chap pap ppp-radius
 ppp authorization network-radius
 ppp multilink
 ppp multilink fragment disable
!

Here is the error I get (LNS) :

.Jun 22 11:39:50.693: ppp206 LCP: O CONFREQ [REQsent] id 5 len 34
.Jun 22 11:39:50.693: ppp206 LCP:    AuthProto CHAP (0x0305C22305)
.Jun 22 11:39:50.693: ppp206 LCP:    MagicNumber 0x45BC4C4D (0x050645BC4C4D)
.Jun 22 11:39:50.693: ppp206 LCP:    MRRU 1524 (0x110405F4)
.Jun 22 11:39:50.693: ppp206 LCP:    EndpointDisc 1 cisco-01 (0x130F016C6E732D544C5333312D3031)
.Jun 22 11:39:50.693: ppp206 LCP: Event[Timeout+] State[REQsent to REQsent]

.Jun 22 11:39:52.709: ppp206 LCP: O CONFREQ [REQsent] id 6 len 34
.Jun 22 11:39:52.709: ppp206 LCP:    AuthProto CHAP (0x0305C22305)
.Jun 22 11:39:52.709: ppp206 LCP:    MagicNumber 0x45BC4C4D (0x050645BC4C4D)
.Jun 22 11:39:52.709: ppp206 LCP:    MRRU 1524 (0x110405F4)
.Jun 22 11:39:52.709: ppp206 LCP:    EndpointDisc 1 cisco-01 (0x130F016C6E732D544C5333312D3031)
.Jun 22 11:39:52.709: ppp206 LCP: Event[Timeout+] State[REQsent to REQsent]

.Jun 22 11:39:54.724: ppp206 LCP: O CONFREQ [REQsent] id 7 len 34
.Jun 22 11:39:54.724: ppp206 LCP:    AuthProto CHAP (0x0305C22305)
.Jun 22 11:39:54.725: ppp206 LCP:    MagicNumber 0x45BC4C4D (0x050645BC4C4D)
.Jun 22 11:39:54.725: ppp206 LCP:    MRRU 1524 (0x110405F4)
.Jun 22 11:39:54.725: ppp206 LCP:    EndpointDisc 1 cisco-01 (0x130F016C6E732D544C5333312D3031)
.Jun 22 11:39:54.725: ppp206 LCP: Event[Timeout+] State[REQsent to REQsent]

.Jun 22 11:39:56.741: ppp206 LCP: O CONFREQ [REQsent] id 8 len 34
.Jun 22 11:39:56.741: ppp206 LCP:    AuthProto CHAP (0x0305C22305)
.Jun 22 11:39:56.741: ppp206 LCP:    MagicNumber 0x45BC4C4D (0x050645BC4C4D)
.Jun 22 11:39:56.741: ppp206 LCP:    MRRU 1524 (0x110405F4)
.Jun 22 11:39:56.741: ppp206 LCP:    EndpointDisc 1 cisco-01 (0x130F016C6E732D544C5333312D3031)
.Jun 22 11:39:56.741: ppp206 LCP: Event[Timeout+] State[REQsent to REQsent]

.Jun 22 11:39:58.757: ppp206 LCP: O CONFREQ [REQsent] id 9 len 34
.Jun 22 11:39:58.757: ppp206 LCP:    AuthProto CHAP (0x0305C22305)
.Jun 22 11:39:58.757: ppp206 LCP:    MagicNumber 0x45BC4C4D (0x050645BC4C4D)
.Jun 22 11:39:58.757: ppp206 LCP:    MRRU 1524 (0x110405F4)
.Jun 22 11:39:58.757: ppp206 LCP:    EndpointDisc 1 cisco-01 (0x130F016C6E732D544C5333312D3031)
.Jun 22 11:39:58.758: ppp206 LCP: Event[Timeout+] State[REQsent to REQsent]

.Jun 22 11:40:00.773: ppp206 LCP: O CONFREQ [REQsent] id 10 len 34
.Jun 22 11:40:00.773: ppp206 LCP:    AuthProto CHAP (0x0305C22305)
.Jun 22 11:40:00.773: ppp206 LCP:    MagicNumber 0x45BC4C4D (0x050645BC4C4D)
.Jun 22 11:40:00.773: ppp206 LCP:    MRRU 1524 (0x110405F4)
.Jun 22 11:40:00.773: ppp206 LCP:    EndpointDisc 1 cisco-01 (0x130F016C6E732D544C5333312D3031)
.Jun 22 11:40:00.773: ppp206 LCP: Event[Timeout+] State[REQsent to REQsent]

.Jun 22 11:40:02.789: ppp206 PPP DISC: LCP failed to negotiate
.Jun 22 11:40:02.789: ppp206 PPP: Sending Acct Event[Down] id[C5EED]
.Jun 22 11:40:02.789: PPP: NET STOP send to AAA.
.Jun 22 11:40:02.789: ppp206 LCP: Event[Timeout-] State[REQsent to Stopped]
.Jun 22 11:40:02.789: ppp206 LCP: Event[DOWN] State[Stopped to Starting]
.Jun 22 11:40:02.789: ppp206 PPP: Phase is DOWN
.Jun 22 11:40:03.468: PPP: Alloc Context [7F41F9B063E8]
.Jun 22 11:40:03.468: ppp207 PPP: Phase is ESTABLISHING
.Jun 22 11:40:03.468: ppp207 LCP: Event[OPEN] State[Initial to Starting]
.Jun 22 11:40:03.469: ppp207 LCP: O CONFREQ [Starting] id 1 len 34

I'm stuck, any ideas ?

THANKS.

MHM Cisco World · ‎06-22-2024

Can I see full config of CEP

MHM

sebastien3 · ‎06-22-2024

I don't have any other configuration to give for the LNS and CPE... It's just missing the loopback but nothing important !

MHM Cisco World · ‎06-22-2024

There is l2tp between lns and lac

And there is pppoe between cpe and lns

As I see you missing some command in cpe for pppoe

That make your config not success

below link for command missing

https://www.cisco.com/c/en/us/support/docs/long-reach-ethernet-lre-digital-subscriber-line-xdsl/asymmetric-digital-subscriber-line-adsl/4105-2600pppoe-4105.html

MHM

sebastien3 · ‎06-23-2024

Hi @MHM Cisco World

Here I am authenticating a Dialer (Cellular SIM) on an LTE network.

Here is the callflow for how this authentication works :

1 => Radius LTE queries Radius Customer to obtain the end of the LNS tunnel.
2 => LNS Customer queries Radius Customer to retrieve the IP to be sent to the SIM card (Dialer).

MHM Cisco World · ‎06-24-2024

Sorry

I am busy now
hope other can help you

Goodluck

MHM

Giuseppe Larosa · ‎06-24-2024

Hello @sebastien3 ,

your debug shows only outobound packets

>>

Jun 22 11:39:56.741: ppp206 LCP: O CONFREQ [REQsent] id 8 len 34

there is nothing coming back.

Probably there is something missing in your configuration and this is not a simple setup.

Hope to help

Giuseppe