[asterisk-users] Help me understand these log messages

[Chris Gentle]

OK, I need a bit of help here.  I'm configuring a new Asterisk 11
system and I accidentally let my firewall rules drop for a day or so.
When I logged in today, I found messages like the ones below on my
asterisk console.  Obviously somebody was trying to take advantage of
my carelessness.  So can someone explain what would cause these types
of messages to show up on my console?

I understand that my iptables would have stopped this but I'm just
trying to understand more about the problem.  What other settings
might have stopped this?  Fail2ban was running but there were no
"failed registration" type messages that would have triggered it.

[May 31 01:47:40] NOTICE[2544][C-00000001] chan_sip.c: Call from ''
(188.161.238.232:28203) to extension '972595595767' rejected because
extension not found in context 'default'.
[May 31 01:47:40] VERBOSE[2544][C-00000002] netsock2.c:   == Using SIP
RTP CoS mark 5
[May 31 01:47:40] NOTICE[2544][C-00000002] chan_sip.c: Call from ''
(188.161.238.232:28203) to extension '00972595595767' rejected because
extension not found in context 'default'.
[May 31 01:47:41] VERBOSE[2544][C-00000003] netsock2.c:   == Using SIP
RTP CoS mark 5
[May 31 01:47:41] NOTICE[2544][C-00000003] chan_sip.c: Call from ''
(188.161.238.232:28203) to extension '000972595595767' rejected
because extension not found in context 'default'.
[May 31 01:47:41] VERBOSE[2544][C-00000004] netsock2.c:   == Using SIP
RTP CoS mark 5
[May 31 01:47:41] NOTICE[2544][C-00000004] chan_sip.c: Call from ''
(188.161.238.232:28203) to extension '011972595595767' rejected
because extension not found in context 'default'.
<snip>


--
Chris