[asterisk-security] Person Trying to Register on my Asterisk multiple times

[Christopher Gray]

Hello:

Beginning on January 6, it appears that somebody has been trying to hack into 
my Asterisk.  They have tried on the 7th, 9th, and the 20th.  The messages file 
in /var/log/Asterisk shows entries like this:

[Jan 20 13:39:40] NOTICE[5130] chan_sip.c: Registration from 
'"1072963462"<sip:1072963462 at 198.144.206.28>' failed for '212.174.78.60' - No matching peer found

[Jan 20 13:39:41] NOTICE[5130] chan_sip.c: Registration from 
'"100"<sip:100 at 198.144.206.28>' failed for '212.174.78.60' - No matching peer found

[Jan 20 13:39:41] NOTICE[5130] chan_sip.c: Registration from 
'"101"<sip:101 at 198.144.206.28>' failed for '212.174.78.60' - No matching peer found

[Jan 20 13:39:41] NOTICE[5130] chan_sip.c: Registration from 
'"102"<sip:102 at 198.144.206.28>' failed for '212.174.78.60' - No matching peer found

[Jan 20 13:39:41] NOTICE[5130] chan_sip.c: Registration from 
'"103"<sip:103 at 198.144.206.28>' failed for '212.174.78.60' - No matching peer found

The sip:101 sip:102 and so on goes up until sip:9975.  This began at 13:39:40 
and ended at 13:42:51.  Entries began at line 970 of the log file and ended at 
8016 for a total of 7,041 occurrences.

How worried should I be about this and what should I do to stop further 
attempts?

Thanks for any advice.

Chris