关于E-140W-P系统安全记录，是不是有人在入侵？

pengl27

使用E-140W-P一段时间了，最近发现系统安全记录中有如下警告信息，请教大神，这是不是网络入侵？该怎么防范？

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2017-04-27 20:14:09	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=123.207.25.215 DST=124.229.21.197 LEN=40 TOS=0x00 PREC=0x00 TTL=245 ID=9664 PROTO=TCP SPT=58816 DPT=1433 WINDOW=1024 RES=0x00 SYN URGP=0 MARK=0x8000000
2017-04-27 20:15:43	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=103.27.5.1 DST=124.229.21.197 LEN=48 TOS=0x00 PREC=0x00 TTL=120 ID=31413 DF PROTO=TCP SPT=54619 DPT=23 WINDOW=8192 RES=0x00 SYN URGP=0 MARK=0x8000000
2017-04-27 20:15:47	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=123.249.27.192 DST=124.229.21.197 LEN=40 TOS=0x00 PREC=0x00 TTL=119 ID=256 PROTO=TCP SPT=650 DPT=8998 WINDOW=16384 RES=0x00 SYN URGP=0 MARK=0x8000000
2017-04-27 20:16:49	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=31.162.150.77 DST=124.229.21.197 LEN=40 TOS=0x00 PREC=0x00 TTL=53 ID=19429 PROTO=TCP SPT=40284 DPT=23 WINDOW=36684 RES=0x00 SYN URGP=0 MARK=0x8000000
2017-04-27 20:18:13	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=103.51.147.246 DST=124.229.21.197 LEN=44 TOS=0x00 PREC=0x00 TTL=114 ID=256 PROTO=TCP SPT=42580 DPT=9999 WINDOW=16384 RES=0x00 SYN URGP=0 MARK=0x8000000
2017-04-27 20:18:17	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=117.217.106.71 DST=124.229.21.197 LEN=40 TOS=0x00 PREC=0x00 TTL=41 ID=62659 PROTO=TCP SPT=21931 DPT=22 WINDOW=30095 RES=0x00 SYN URGP=0 MARK=0x8000000
2017-04-27 20:18:35	kern	1	alert	kernel: Intrusion -> IN=ppp0.1 OUT= MAC= SRC=61.139.175.80 DST=124.229.21.197 LEN=40 TOS=0x00 PREC=0x00 TTL=109 ID=256 PROTO=TCP SPT=6000 DPT=1433 WINDOW=16384 RES=0x00 SYN URGP=0 MARK=0x8000000

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