* Android  9 & 10 fails on maximum retries exceeded for tunnel

There are reports that with Android 9 & 10, some users are getting "Maximum retries"
error messages. It seems to related to some of the phones not responding to
L2TP keepalive heartbeats

A possible work around is to use the max_retries option. Using "max retries"
in the xl2tpd.conf (e.g. max retries = 100) has known to work for some
users. Alternatively, another works around is to not to enable L2TP
keepalive on the VPN servers.

For more information, please refer to: https://github.com/xelerance/xl2tpd/issues/191

* Issues with Cisco ASA

Some users are reporting that newer version of xl2tpd (1.310 onward) are
not able to connect to Cisco ASA.

A possible work around is to use x2ltpd 1.39 and disable use of kernel module
(comment out the directive OSFLAGS+= -DUSE_KERNEL -D in the Makefile)

For more information, please refer to: https://github.com/xelerance/xl2tpd/issues/187

* AVP is incorrect size issues with Miktrotik server

There are reports of problems connecting to Miktrotik server.

Github user reported that the following configuration works for them:
https://github.com/xelerance/xl2tpd/issues/156#issuecomment-678674101

* Out of order control packet on tunnel

Some users are reporting when stablishing a tunnel with with Watchguard
Firewall, they get "Out of order control packet on tunnel" error messages.
If that is the case, please add the following to the DFLAGS section in Makefile
and compile:
    -DCONFIG_WATCHDOG_FIREWALL

* Some ISP use l2tp without IPsec.

If the ISP being used by end user does not use IPsec, please comment out the
following in debian/xl2tpd.service file:
    After=ipsec.service
    Wants=ipsec.service