MTU on Virtual-Template (LNS/PPP)

[sebastien3]

Hello,

A router in LNS configuration with the following configuration :

vpdn enable
!
vpdn-group TEST
 accept-dialin
  protocol l2tp
  virtual-template 1
 source-ip A.B.C.D
 local name L2TP-1
 lcp renegotiation always
 no l2tp tunnel authentication
 ip mtu adjust
!
interface Virtual-Template1
 ip unnumbered Loopback1
 no ip redirects
 no ip proxy-arp
 ip mtu 1300
 ip verify unicast source reachable-via rx
 ip tcp adjust-mss 1260
 ppp mtu adaptive
 ppp authentication chap ppp-radius
 ppp authorization network-radius
 ppp multilink
 ppp multilink fragment disable
!

Does the Virtual-Template1 interface auto-configure the client with the MTU (1300) ? I ask the question because I have a doubt...

On the router (client ppp) I can ping higher than 1300 ! The ping works up to 1500 :

Cisco_RTR#ping 8.8.8.8 size 1500 df-bit
Type escape sequence to abort.
Sending 5, 1500-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:
Packet sent with the DF bit set
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 104/113/128 ms

Thank you for your explanation

[MHM Cisco World]

 ppp mtu adaptive

this command make the issue, 
adaptive mtu meaning that LNS use the MTU the client use not the mtu config under the virtual-template. 
this I think issue here, remove it and check again 

[sebastien3]

No, it doesn't change anything, I've already done the test with or without ppp mtu adaptive.

The test client router uses a virtual-ppp interface with pseudowire-class. Could the problem come from this ?

[MHM Cisco World]

with and without, are you force the client to initiate new PPP ?

[sebastien3]

Of course I reloaded the test client router !

[MHM Cisco World]

can I see the LNS/LAC and client config ?

[sebastien3]

There is no LAC... The configuration of the LNS/L2TP server is in the first message.

Here the configuration of test router :

l2tp-class TEST
!
pseudowire-class CL-PW
 encapsulation l2tpv2
 protocol l2tpv2 TEST
 ip local interface GigabitEthernet8
!
interface GigabitEthernet8
 description * WAN *
 ip address dhcp
 no ip redirects
 no ip proxy-arp
 ip nat outside
 ip virtual-reassembly in
 duplex auto
 speed auto
 no cdp enable
!
interface Virtual-PPP1
 ip address negotiated
 ip nat outside
 ip virtual-reassembly in
 no cdp enable
 ppp chap hostname cisco@test.com
 ppp chap password 7 045A11031D3555
 pseudowire A.B.C.D 10 encapsulation l2tpv2 pw-class CL-PW
!

[sebastien3]

No idea ?