Today i found those logs on my MikroTik RB2011UiAS-2HnD (Screenshot #1). Not long ago i allowed pptp (pptp+gre in the firewall). Later i created few vpn users for connection to pptp. But today i was shocked when i saw those logs (i don't know this IPs). Then I checked when my vpn-users authorized on pptp server and saw this picture(Screenshot #2). Nobody from users had't connection with my pptp server on MikroTik in that time. What does logs on the screenshot #1 means? Can somebody explain me?

It means someone trying to get in. These messages are written for every attempt, successful or unsuccessful. For unsuccessful authentication typically there are no additional messages (default configuration). If authentication was successful, there should be message like 'username logged in'.

Just allow remote connections for predefined ip pools you know they need you.

It means someone trying to get in. These messages are written for every attempt, successful or unsuccessful. For unsuccessful authentication typically there are no additional messages (default configuration). If authentication was successful, there should be message like 'username logged in'.

Successful attemp like that(screenshot #1)?

Just allow remote connections for predefined ip pools you know they need you.

I think about that coz access to this router realized like you told.