What does it mean when an IP address conflicts with other systems on the network? Filter malicious IPs

// 过滤恶意IP
function deny_bad_ip($kmLoginIP){
	$bad_ip_arr = array();
	$bad_ip_sql = "select ip,count(ip) num from anlene_join_user group by ip having num>100"; // 获取恶意ip
	$bad_ip_rs = mysql_query($bad_ip_sql);
	while($bad_ip_row = mysql_fetch_assoc($bad_ip_rs)){
		$bad_ip_arr[] = $bad_ip_row['ip'];
	}
	if(in_array($kmLoginIP, $bad_ip_arr)){
		return true;
	}else{
		return false;
	}
}

The above introduces what does it mean when an IP address conflicts with other systems on the network, and how to filter malicious IPs, including what does it mean when an IP address conflicts with other systems on the network. I hope friends who are interested in PHP tutorials can learn from it. help.