L2TPv3 tunnel private IPs not working

Question

I'm trying to setup L2TPv3 tunnel between 2 servers - CentOS 7 and Ubuntu 16

On CentOS 7 end I have the following:

ip l2tp add tunnel tunnel_id 6000 peer_tunnel_id 5000 encap udp local LOCAL_IP remote REMOTE_IP udp_sport 5002 udp_dport 6002
ip l2tp add session tunnel_id 6000 session_id 1000 peer_session_id 2000
ip link set l2tpeth0 up mtu 1488
ip addr add 10.0.3.2 peer 10.0.3.1 dev l2tpeth0

On Ubuntu 16 I have the following

ip l2tp add tunnel tunnel_id 3000 peer_tunnel_id 4000 encap udp local LOCAL_IP remote REMOTE_IP udp_sport 5001 udp_dport 6001
ip l2tp add session tunnel_id 3000 session_id 2000 peer_session_id 1000
ip link set l2tpeth1 up mtu 1488
ip addr add 10.0.3.1 peer 10.0.3.2 dev l2tpeth1

The tunnel is setup successfully after that

root@srv1057:~# ip l2tp show tunnel
Tunnel 6000, encap UDP
  From LOCAL_IP to REMOTE_IP
  Peer tunnel 5000
  UDP source / dest ports: 5002/6002

root@srv1057:~# ip l2tp show session
Session 1000 in tunnel 6000
  Peer session 2000, tunnel 5000
  interface name: l2tpeth0
  offset 0, peer offset 0

[root@localhost ~]# ip l2tp show tunnel
Tunnel 5000, encap UDP
  From LOCAL_IP to REMOTE_IP
  Peer tunnel 6000
  UDP source / dest ports: 5002/6002


[root@localhost ~]# ip l2tp show session
Session 2000 in tunnel 5000
  Peer session 1000, tunnel 6000
  interface name: l2tpeth2
  offset 0, peer offset 0

One end private IP is 10.0.3.1 and another end is 10.0.3.2

Can't ping each other IP.

[root@localhost ~]# ping 10.0.3.2
PING 10.0.3.2 (10.0.3.2) 56(84) bytes of data.
From 10.0.3.1 icmp_seq=1 Destination Host Unreachable
From 10.0.3.1 icmp_seq=2 Destination Host Unreachable
From 10.0.3.1 icmp_seq=3 Destination Host Unreachable
From 10.0.3.1 icmp_seq=4 Destination Host Unreachable
^C
--- 10.0.3.2 ping statistics ---
6 packets transmitted, 0 received, +4 errors, 100% packet loss, time 5001ms
pipe 4

Network end(switch and routers) should be fine, as I can establish connectivity between in GRE tunnel on same private range without any issues, just L2TPv3 is messing.

Notes:

1) ip forwarding enabled in /etc/sysctl.conf in both servers

2) iptables / firewall / ufw disabled on all servers

Any insight on this would be appreciated!

Thanks

Answer 1

Ubuntu load automatic module l2tp_eth

only for CentOS 7

modprobe l2tp_eth

and both server add dev l2tpeth0, unless you have more than one l2tunnel