lots of UDP_IN Blocked errors

Since I have reinstalled my OS, I’m getting lots of UDP_IN Blocked errors in my messages log. Can anyone kindly explain what the error say exactly and what I can do to get rid of this error.

Aug  8 22:02:19 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:f6:f3:49:7e:0a:54:08:00 SRC=178.162.xxx.xx DST=178.162.xxx.xxx LEN=131 TOS=0x00 PREC=0x00 TTL=128 ID=11061 PROTO=UDP SPT=17500 DPT=17500 LEN=111
Aug  8 22:02:22 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:ba:08:45:88:fc:a1:08:00 SRC=192.168.x.xx DST=255.255.255.255 LEN=68 TOS=0x00 PREC=0x00 TTL=128 ID=13132 PROTO=UDP SPT=58878 DPT=1947 LEN=48
Aug  8 22:02:49 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:f6:f3:49:7e:0a:54:08:00 SRC=178.162.xxx.xx DST=255.255.255.255 LEN=131 TOS=0x00 PREC=0x00 TTL=128 ID=12046 PROTO=UDP SPT=17500 DPT=17500 LEN=111
Aug  8 22:02:49 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:f6:f3:49:7e:0a:54:08:00 SRC=178.162.xxx.xx DST=178.162.xxx.xxx LEN=131 TOS=0x00 PREC=0x00 TTL=128 ID=12047 PROTO=UDP SPT=17500 DPT=17500 LEN=111
Aug  8 22:03:01 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:ba:08:45:88:fc:a1:08:00 SRC=192.168.x.xx DST=255.255.255.255 LEN=68 TOS=0x00 PREC=0x00 TTL=128 ID=13134 PROTO=UDP SPT=58878 DPT=1947 LEN=48
Aug  8 22:03:12 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:62:83:46:e6:0d:15:08:00 SRC=178.162.xxx.xxx DST=255.255.255.255 LEN=115 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=5678 DPT=5678 LEN=95
Aug  8 22:03:19 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:f6:f3:49:7e:0a:54:08:00 SRC=178.162.xxx.xx DST=255.255.255.255 LEN=131 TOS=0x00 PREC=0x00 TTL=128 ID=13070 PROTO=UDP SPT=17500 DPT=17500 LEN=111
Aug  8 22:03:19 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:f6:f3:49:7e:0a:54:08:00 SRC=178.162.xxx.xx DST=178.162.xxx.xxx LEN=131 TOS=0x00 PREC=0x00 TTL=128 ID=13071 PROTO=UDP SPT=17500 DPT=17500 LEN=111
Aug  8 22:03:39 server kernel: Firewall: *UDP_IN Blocked* IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:ba:08:45:88:fc:a1:08:00 SRC=192.168.x.xx DST=255.255.255.255 LEN=68 TOS=0x00 PREC=0x00 TTL=128 ID=13136 PROTO=UDP SPT=58878 DPT=1947 LEN=48

Issuing the iptables-save yields the following:

# Generated by iptables-save v1.4.7 on Fri Aug  8 16:42:05 2014
*mangle
:PREROUTING ACCEPT [158298:41039552]
:INPUT ACCEPT [131187:38557000]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [79668:17293129]
:POSTROUTING ACCEPT [79637:17291305]
COMMIT
# Completed on Fri Aug  8 16:42:05 2014
# Generated by iptables-save v1.4.7 on Fri Aug  8 16:42:05 2014
*nat
:PREROUTING ACCEPT [93313:9541674]
:POSTROUTING ACCEPT [896:63899]
:OUTPUT ACCEPT [896:63899]
COMMIT
# Completed on Fri Aug  8 16:42:05 2014
# Generated by iptables-save v1.4.7 on Fri Aug  8 16:42:05 2014
*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
:ALLOWIN - [0:0]
:ALLOWOUT - [0:0]
:CONNLIMIT - [0:0]
:DENYIN - [0:0]
:DENYOUT - [0:0]
:INVALID - [0:0]
:INVDROP - [0:0]
:LOCALINPUT - [0:0]
:LOCALOUTPUT - [0:0]
:LOGDROPIN - [0:0]
:LOGDROPOUT - [0:0]
:PORTFLOOD - [0:0]
-A INPUT -s 8.8.4.4/32 ! -i lo -p tcp -m tcp --dport 53 -j ACCEPT 
-A INPUT -s 8.8.4.4/32 ! -i lo -p udp -m udp --dport 53 -j ACCEPT 
-A INPUT -s 8.8.4.4/32 ! -i lo -p tcp -m tcp --sport 53 -j ACCEPT 
-A INPUT -s 8.8.4.4/32 ! -i lo -p udp -m udp --sport 53 -j ACCEPT 
-A INPUT -s 4.2.2.4/32 ! -i lo -p tcp -m tcp --dport 53 -j ACCEPT 
-A INPUT -s 4.2.2.4/32 ! -i lo -p udp -m udp --dport 53 -j ACCEPT 
-A INPUT -s 4.2.2.4/32 ! -i lo -p tcp -m tcp --sport 53 -j ACCEPT 
-A INPUT -s 4.2.2.4/32 ! -i lo -p udp -m udp --sport 53 -j ACCEPT 
-A INPUT ! -i lo -j LOCALINPUT 
-A INPUT -i lo -j ACCEPT 
-A INPUT ! -i lo -p tcp -j INVALID 
-A INPUT ! -i lo -p tcp -m tcp --dport 22 -m state --state NEW -m recent --set --name 22 --rsource 
-A INPUT ! -i lo -p tcp -m tcp --dport 22 -m state --state NEW -m recent --update --seconds 250 --hitcount 2 --name 22 --rsource -j PORTFLOOD 
-A INPUT ! -i lo -p tcp -m tcp --dport 22 --tcp-flags FIN,SYN,RST,ACK SYN -m connlimit --connlimit-above 2 --connlimit-mask 32 -j CONNLIMIT 
-A INPUT ! -i lo -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 20 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 21 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 53 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 110 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 587 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 995 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 2222 -j ACCEPT 
-A INPUT ! -i lo -p tcp -m state --state NEW -m tcp --dport 46734 -j ACCEPT 
-A INPUT ! -i lo -p udp -m state --state NEW -m udp --dport 20 -j ACCEPT 
-A INPUT ! -i lo -p udp -m state --state NEW -m udp --dport 21 -j ACCEPT 
-A INPUT ! -i lo -p udp -m state --state NEW -m udp --dport 53 -j ACCEPT 
-A INPUT ! -i lo -p icmp -m icmp --icmp-type 8 -m limit --limit 1/sec -j ACCEPT 
-A INPUT ! -i lo -p icmp -m icmp --icmp-type 0 -m limit --limit 1/sec -j ACCEPT 
-A INPUT ! -i lo -p icmp -m icmp --icmp-type 11 -j ACCEPT 
-A INPUT ! -i lo -p icmp -m icmp --icmp-type 3 -j ACCEPT 
-A INPUT ! -i lo -j LOGDROPIN 
-A OUTPUT -d 8.8.4.4/32 ! -o lo -p tcp -m tcp --dport 53 -j ACCEPT 
-A OUTPUT -d 8.8.4.4/32 ! -o lo -p udp -m udp --dport 53 -j ACCEPT 
-A OUTPUT -d 8.8.4.4/32 ! -o lo -p tcp -m tcp --sport 53 -j ACCEPT 
-A OUTPUT -d 8.8.4.4/32 ! -o lo -p udp -m udp --sport 53 -j ACCEPT 
-A OUTPUT -d 4.2.2.4/32 ! -o lo -p tcp -m tcp --dport 53 -j ACCEPT 
-A OUTPUT -d 4.2.2.4/32 ! -o lo -p udp -m udp --dport 53 -j ACCEPT 
-A OUTPUT -d 4.2.2.4/32 ! -o lo -p tcp -m tcp --sport 53 -j ACCEPT 
-A OUTPUT -d 4.2.2.4/32 ! -o lo -p udp -m udp --sport 53 -j ACCEPT 
-A OUTPUT ! -o lo -j LOCALOUTPUT 
-A OUTPUT ! -o lo -p tcp -m tcp --dport 53 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m udp --dport 53 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m tcp --sport 53 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m udp --sport 53 -j ACCEPT 
-A OUTPUT -o lo -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -j INVALID 
-A OUTPUT ! -o lo -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 20 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 21 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 53 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 110 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 113 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 2222 -j ACCEPT 
-A OUTPUT ! -o lo -p tcp -m state --state NEW -m tcp --dport 46734 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m state --state NEW -m udp --dport 20 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m state --state NEW -m udp --dport 21 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m state --state NEW -m udp --dport 53 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m state --state NEW -m udp --dport 113 -j ACCEPT 
-A OUTPUT ! -o lo -p udp -m state --state NEW -m udp --dport 123 -j ACCEPT 
-A OUTPUT ! -o lo -p icmp -m icmp --icmp-type 0 -j ACCEPT 
-A OUTPUT ! -o lo -p icmp -m icmp --icmp-type 8 -j ACCEPT 
-A OUTPUT ! -o lo -p icmp -m icmp --icmp-type 11 -j ACCEPT 
-A OUTPUT ! -o lo -p icmp -m icmp --icmp-type 3 -j ACCEPT 
-A OUTPUT ! -o lo -j LOGDROPOUT 
-A ALLOWIN -s 37.254.xxx.xxx/32 ! -i lo -j ACCEPT 
-A ALLOWOUT -d 37.254.xxx.xxx/32 ! -o lo -j ACCEPT 
-A CONNLIMIT -p tcp -j REJECT --reject-with tcp-reset 
-A DENYIN -s 97.77.xxx.xxx/32 ! -i lo -j DROP 
-A DENYOUT -d 97.77.xxx.xxx/32 ! -o lo -j LOGDROPOUT 
-A INVALID -m state --state INVALID -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,SYN,RST,PSH,ACK,URG -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags FIN,SYN FIN,SYN -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags SYN,RST SYN,RST -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags FIN,RST FIN,RST -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags FIN,ACK FIN -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags PSH,ACK PSH -j INVDROP 
-A INVALID -p tcp -m tcp --tcp-flags ACK,URG URG -j INVDROP 
-A INVALID -p tcp -m tcp ! --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j INVDROP 
-A INVDROP -j DROP 
-A LOCALINPUT ! -i lo -j ALLOWIN 
-A LOCALINPUT ! -i lo -j DENYIN 
-A LOCALOUTPUT ! -o lo -j ALLOWOUT 
-A LOCALOUTPUT ! -o lo -j DENYOUT 
-A LOGDROPIN -p tcp -m tcp --dport 67 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 67 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 68 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 68 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 111 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 111 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 113 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 113 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 135:139 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 135:139 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 445 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 445 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 500 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 500 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 513 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 513 -j DROP 
-A LOGDROPIN -p tcp -m tcp --dport 520 -j DROP 
-A LOGDROPIN -p udp -m udp --dport 520 -j DROP 
-A LOGDROPIN -p tcp -m limit --limit 30/min -j LOG --log-prefix "Firewall: *TCP_IN Blocked* " 
-A LOGDROPIN -p udp -m limit --limit 30/min -j LOG --log-prefix "Firewall: *UDP_IN Blocked* " 
-A LOGDROPIN -p icmp -m limit --limit 30/min -j LOG --log-prefix "Firewall: *ICMP_IN Blocked* " 
-A LOGDROPIN -j DROP 
-A LOGDROPOUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -m limit --limit 30/min -j LOG --log-prefix "Firewall: *TCP_OUT Blocked* " --log-uid 
-A LOGDROPOUT -p udp -m limit --limit 30/min -j LOG --log-prefix "Firewall: *UDP_OUT Blocked* " --log-uid 
-A LOGDROPOUT -p icmp -m limit --limit 30/min -j LOG --log-prefix "Firewall: *ICMP_OUT Blocked* " --log-uid 
-A LOGDROPOUT -j DROP 
-A PORTFLOOD -m limit --limit 30/min -j LOG --log-prefix "Firewall: *Port Flood* " 
-A PORTFLOOD -j DROP 
COMMIT
# Completed on Fri Aug  8 16:42:05 2014

Since I have used CSF for configuring my firewall, I will attach only the lines I have touched.

TESTING = "0"

TESTING_INTERVAL = "5"

RESTRICT_SYSLOG = "3"

RESTRICT_SYSLOG_GROUP = "mysyslog"

RESTRICT_UI = "1"

AUTO_UPDATES = "1"

TCP_IN = "20,21,22,25,53,80,110,443,587,995,2222,46734"

TCP_OUT = "20,21,22,25,53,80,110,113,443,2222,46734"

UDP_IN = "20,21,53"

UDP_OUT = "20,21,53,113,123"

ICMP_IN = "1"

ICMP_IN_RATE = "1/s"

ICMP_OUT = "1"

ICMP_OUT_RATE = "0"

IPV6 = "1"

IPV6_ICMP_STRICT = "0"

IPV6_SPI = "1"

TCP6_IN = "20,21,22,25,53,80,110,443,587,995,2222"

TCP6_OUT = "20,21,22,25,53,80,110,113,443,2222"

UDP6_IN = "20,21,53"

UDP6_OUT = "20,21,53,113,123"

ETH_DEVICE = ""

ETH6_DEVICE = ""

ETH_DEVICE_SKIP = ""

USE_CONNTRACK = "0"

SYSLOG_CHECK = "600"

IGNORE_ALLOW = "0"

DNS_STRICT = "0"

DNS_STRICT_NS = "0"

DENY_IP_LIMIT = "200"

DENY_TEMP_IP_LIMIT = "100"

LF_DAEMON = "1"

LF_CSF = "1"

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