Is it possible to log unsolicited incoming connection attempts that the router firewall has blocked?
Under the Advanced tab (firmware v7.1) I have set a number of Inbound Firewall rules similar to this one for Telnet.
Others I set were for port 3389 RDP, port 5900 VNC, port 2323 Mirai botnet and port 443 TLS. None of them have generated an entry in the Event Log and the rules have been active for a very long time. The router, a Surf SOHO is connected to a modem and then directly to the Internet.