下記のログばかり続いているのですが理由を教えて頂けないでしょうか。
初心者ですお願いします。

2003/10/16 11:32:03 NAT RX Not Found : ICMP 61.215.245.29 > 61.215.*.* (IP-PORT=7)
2003/10/16 11:33:34 NAT RX Not Found : ICMP 61.215.248.239 > 61.215.*.* (IP-PORT=7)
2003/10/16 11:34:23 NAT RX Not Found : ICMP 61.215.0.120 > 61.215.*.* (IP-PORT=7)
2003/10/16 11:37:39 NAT RX Not Found : ICMP 61.214.199.33 > 61.215.*.* (IP-PORT=7)
2003/10/16 11:38:23 NAT RX Not Found : ICMP 61.215.8.95 > 61.215.*.* (IP-PORT=7)
2003/10/16 11:39:42 NAT RX Not Found : ICMP 61.215.253.210 > 61.215.*.* (IP-PORT=7)