You can enable the logging in pflog
nano /etc/rc.d/pflog
/sbin/pflogd restart
You can verify your pflogd service running :
ps ax | grep pflogd
But this log file is binary and you won’t be able to tail it with the ‘clog’ utility in FreeBSD . To clog this file you need to use the tcpdump:
tcpdump -netttr /var/log/pflog
You can thhen filter this with your host IP , port number etc .