I use ufw utility to manage my firewall for the system which runs web and mail services. The rules are follow:
Status: active To Action From -- ------ ---- 22/tcp ALLOW Anywhere 80 ALLOW Anywhere 443 ALLOW Anywhere 143 ALLOW Anywhere 993 ALLOW Anywhere 25/tcp ALLOW Anywhere 587 ALLOW Anywhere ... 22/tcp (v6) ALLOW Anywhere (v6) 80 (v6) ALLOW Anywhere (v6) 443 (v6) ALLOW Anywhere (v6) 143 (v6) ALLOW Anywhere (v6) 993 (v6) ALLOW Anywhere (v6) 25/tcp (v6) ALLOW Anywhere (v6) 587 (v6) ALLOW Anywhere (v6)
But in log files there are a lot of messages of blocked packets to the permitted ports, like:
kernel: [...] [UFW BLOCK] IN=eth0 OUT= MAC=...:83:08:00 SRC=[sourceIP] DST=[myIP] LEN=40 TOS=0x00 PREC=0x00 TTL=52 ID=811 PROTO=TCP SPT=21766 DPT=80 WINDOW=0 RES=0x00 ACK RST URGP=0
or:
kernel: [...] [UFW BLOCK] IN=eth0 OUT= MAC=...:08:00 SRC=[sourceIP] DST=[myIP] LEN=40 TOS=0x00 PREC=0x00 TTL=118 ID=1150 PROTO=TCP SPT=56818 DPT=993 WINDOW=1525 RES=0x00 ACK URGP=0
I do not have any restrictions of firewall for the incoming IP addresses, so what is the reason of such blocks and is there a way to fix it. Thanks a lot.
