今天在 Mimedefang 裡的 filter_recipient 啟用了 Greylist,
因為有兩台 Spam Filter 主機, 所以 DB 就統一寫到 Mysql,
程式自己寫的, 短短的, 效果不錯, 約可擋掉 8 成 Spam.
sub filter_recipient ($$$$$$$$$)
{
use DBI;
# 參數及變數設定
my($recip, $sender, $rest_of_the_junk) = @_;
# ByPass DMZ IP 不須要 RELAY 檢查
if ( ($RelayAddr =~ "xxx.xxx.xxx"))
{ return ("CONTINUE", ""); }
# 設定資料庫連線參數
my $database = "xxxx";
my $host = "xxx.xxx.xxx.xxx";
my $user = "xxxxx";
my $password = "xxxxxxxxxx";
# 尋找 MySQL 裡 EmailUser Address 是否存在
my $dbh = DBI->connect("DBI:mysql:$database;host=$host", $user, $password);
my $sth = $dbh->prepare( "SELECT * FROM emailuser WHERE emailadd LIKE \'$recip\' ");
$sth->execute;
# 若 User 不存在, 則 Reject, 並記錄至資料庫
if ( $sth->rows == 0 )
{
$sth = $dbh->prepare( "INSERT INTO rejectdata( recaddr, sender, hostip, datetime, messageid) VALUES (\"$recip\", \"$sender\", \"$RelayAddr\", now(), \"$MsgID\" )");
$sth->execute;
$dbh->disconnect();
return("REJECT", "User unKnown.");
}
# 寄件者是否在白名單內, 則直接 Continue
$sth = $dbh->prepare( "select sender from white_list where sender like \"$sender\" " );
$sth->execute;
if( $sth->rows > 0 )
{
action_add_header("White-List", "White List Check OK ");
$dbh->disconnect();
# $Sender 在白名單裡, 做紀錄通過白名單並跳出, 回主程式繼續傳送信件
$Features{'White_list'} = 1;
return ("CONTINUE", "");
}
# 查詢灰名單, 是否在紀錄內, 若是, 又超過 300 秒, 則繼續傳送信件
my $timestamp = time;
# 啟動記錄的 DMZ 的主機的 IP
my $ip = 'xxx.xxx.xxx.xxx';
my $tripple = "$RelayAddr/$Sender/".$Recipients[0];
$sth = $dbh->prepare( "select tripple, timestamp from grey_list where tripple like \"$tripple\" " );
$sth->execute;
if( $sth->rows > 0 )
{
my ( $trippledb, $timestampdb) = $sth->fetchrow;
# 時間小於 300 秒, 回覆啟動灰名單
if ( ( $timestamp - $timestampdb ) < 300 )
{
$dbh->disconnect();
return ('TEMPFAIL', 'Greylisting active, please try again later');
}
# 通過灰名單, 砍掉紀錄, 然後 Continue
else
{
my $sth1 = $dbh->prepare( "delete from grey_list where tripple like '$tripple' " );
$sth1->execute;
$dbh->disconnect();
return ("CONTINUE", "");
}
}
# 沒有灰名單紀錄, 塞入灰名單資料庫內
$sth = $dbh->prepare( "INSERT INTO grey_list( tripple, timestamp, datetime, hostip ) VALUES (\"$tripple\", \"$timestamp\", now(), \"$ip\" )" );
$sth->execute;
$dbh->disconnect();
# 回覆啟動灰名單
return ('TEMPFAIL', 'Greylisting active, please try again later');
}
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