<4>Sep 12 22:10:14 hq-postgres kernel: [1137646.330948] [UFW BLOCK] IN=ens5 OUT= MAC=02:da:4a:4d:f8:d0:02:4b:94:bf:cd:44:08:00 SRC=144.186.31.220 DST=227.122.137.198 LEN=52 TOS=0x00 PREC=0x00 TTL=254 ID=17937 DF PROTO=TCP SPT=2049 DPT=743 WINDOW=1502 RES=0x00 ACK 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: 2049
facilitylabel: kernel
localhostname: hq-postgres
localstarttime: Sep 12 22:10:14
messagetype: firewall_action
priority: 4
program: kernel
protocol: 6
senderhost: 10.1.100.75
sensitivity: normal
serverbytes: 52
serverport: 743
severitycode: 4
severitylabel: warning
sourceinfo: unknown
tags: ['rfc3164', 'ufw', 'firewall_action']
streamName: ufw
clientIP: 144.186.31.220
serverIP: 227.122.137.198