<4>Jun  6 18:13:25 hq-postgres kernel: [425830.420689] [UFW BLOCK] IN=ens5 OUT= MAC=02:da:4a:4d:f8:d0:02:4b:94:bf:cd:44:08:00 SRC=238.161.162.57 DST=86.91.39.177 LEN=52 TOS=0x08 PREC=0x60 TTL=37 ID=46889 DF PROTO=TCP SPT=16875 DPT=5432 WINDOW=502 RES=0x00 ACK FIN URGP=0 
This is a syslog message from a product called Uncomplicated Firewall (UFW) by linux. The following fields were extracted from the message:
action: block
clientport: 16875
facilitylabel: kernel
localhostname: hq-postgres
localstarttime: Jun  6 18:13:25
messagetype: firewall_action
priority: 4
program: kernel
protocol: 6
senderhost: 10.1.100.75
sensitivity: normal
serverbytes: 52
serverport: 5432
severitycode: 4
severitylabel: warning
sourceinfo: unknown
tags: ['rfc3164', 'ufw', 'firewall_action']
streamName: ufw
clientIP: 238.161.162.57
serverIP: 86.91.39.177