ArpON 2.7 bug: use -D (--darpi) flag for the DARPI technique by default (/etc/default/arpon file).

Hello.

It seems that there is a bug in a default install of the ArpON 2.7 package. After successful install via 'apt-get' utility, user using a DHCP method to obtain an IP address will receive a following error (during arpon start):

$ sudo /etc/init.d/arpon start
* Starting anti ARP poisoning daemon arpon
20:38:55 PID = </var/run/arpon.pid>

/usr/bin/arpon: invalid option -- 'd' [fail]

It happens, because by default in the '/etc/default/arpon' file there is a line with a small bug. By default a line responsible for a DARPI technique looks this way:

DAEMON_OPTS="-q -f /var/log/arpon/arpon.log -g -d"

As we can see there is a '-d' flag, which was okay but in ArpON 2.0-2.1 version (available e.g. in Precise, Trusty releases etc.) A new, 2.7.2-1 version (available e.g. in Vivid release), should use '-D' flag but even in a new ArpON version still, there is a '-d' flag, which leads to the "invalid option" problem (please see above).

According to the Ubuntu manpage '-g' flag stands for "Works in logging mode", since '-D' flag means "Manages Arp Cache dynamically". So, '/etc/default/arpon' file should/could contain a correct flag: -D (--darpi). The solution is simple:

--- a/ DAEMON_OPTS="-q -f /var/log/arpon/arpon.log -g -d"
+++ b/ DAEMON_OPTS="-q -f /var/log/arpon/arpon.log -g -D"

After this small change, everything started to work okay:

$ sudo /etc/init.d/arpon start
* Starting anti ARP poisoning daemon arpon
20:43:32 PID = </var/run/arpon.pid> [OK]

One more test, to be one hundred percent sure: status of anti ARP poisoning daemon arpon is [OK] after running 'sudo /etc/init.d/arpon status' command.

Summing up: ArpON 2.7 version still uses a '-d' flag (what's causing the problem) instead of '-D'. I think, that this one line in the '/etc/default/arpon' file should be changed (see above).

Thankfully, ArpON 2.7 version manpage (see: http://manpages.ubuntu.com/manpages/vivid/man8/arpon.8.html) contains correct informations, but I think that mentioned solution is needed because of many reason. Especially from an user point of view etc.

Best regards.