/etc/xl2tpd.conf:

[global]								; Global parameters:
ipsec saref = yes

[lns default]
ip range = 192.168.101.40-192.168.101.50
local ip = 192.168.101.1
require chap = yes
refuse pap = yes
require authentication = yes
name = VPN-Server
ppp debug = yes
pppoptfile = /etc/ppp/options.xl2tpd
length bit = yes


/etc/ppp/options.xl2tpd	

# This file is filled with comments. I took them all out.
require-mschap-v2
ms-dns 123.456.789.123
asyncmap 0
auth
#noauth
crtscts
lock
hide-password
#modem
ebug
name l2tpd
proxyarp
lcp-echo-interval 30
lcp-echo-failure 4


/var/log/syslog output:

xl2tpd[18558]: control_finish: Peer requested tunnel 86 twice, ignoring second one.
xl2tpd[18558]: control_finish: Peer requested tunnel 86 twice, ignoring second one.
xl2tpd[18558]: control_finish: Peer requested tunnel 86 twice, ignoring second one.
xl2tpd[18558]: Maximum retries exceeded for tunnel 35711.  Closing.
xl2tpd[18558]: control_finish: Peer requested tunnel 86 twice, ignoring second one.
xl2tpd[18558]: Connection 86 closed to 111.222.333.444, port 57194 (Timeout)
xl2tpd[18558]: Unable to deliver closing message for tunnel 35711. Destroying anyway.