Please have a look at these entries in an old mailbox.log file,

Code:
2012-05-20 17:05:14,264 INFO  [btpool0-17://mail.example.com:7071/service/admin/soap/] [name=admin@example.com;ip=192.168.52.80;] SoapEngine - handler exception: authentication failed for abuse, invalid password
2012-05-20 23:17:34,802 INFO  [btpool0-18://mail.example.com:7071/service/admin/soap/] [ip=192.168.52.80;] SoapEngine - handler exception: authentication failed for test, account not found
2012-05-20 23:17:35,892 INFO  [btpool0-18://mail.example.com:7071/service/admin/soap/] [ip=192.168.52.80;] SoapEngine - handler exception: authentication failed for info, account not found
2012-05-20 23:17:36,987 INFO  [btpool0-20://mail.example.com:7071/service/admin/soap/] [name=admin@example.com;ip=192.168.52.80;] SoapEngine - handler exception: authentication failed for admin, invalid password
2012-05-20 23:17:41,052 INFO  [btpool0-18://mail.example.com:7071/service/admin/soap/] [ip=192.168.52.80;] SoapEngine - handler exception: authentication failed for webmaster, account not found
I don't understand where these failed login attempts originate, e.g. is it from the admin console because it says mail.example.com:7071 or is it from the LAN because the server's IP is shown?

I have very strong passwords on all accounts and failed login policy enabled. The admin console is only accessible on the LAN and the server is behind a firewall with ports 443, 587, 993 and 25 open.

How concerned should I be regarding the entries shown above?