脚本功能：通过ICMP Ping或TCP/SYN探测指定的域名，探测前检测域名是否有效。
file: check.host.pl
#!/usr/bin/perl
use strict;
use Net::Ping;
use Net::DNS;
use Time::HiRes qw();
$| = 1;
my $DEFAULT_TIMEOUT = 2;
my $PING_TIMEOUT = 2;
my $DNS_TIMEOUT = 3;
### 查询域名是否有效
sub queryDomain {
my $domain = shift();
my $query = \’\’;
my $dns = Net::DNS::Resolver->new(
tcp_timeout => $DNS_TIMEOUT, udp_timeout => $DNS_TIMEOUT, retry => 1
);
my @nameservers = qw/8.8.8.8 114.114.114.114/;
$dns->nameservers(@nameservers);
eval {
$query = $dns->search($domain,\’A\’);
};
if ($@ or ! $query) {
my $err = $dns->errorstring ;
print \”ERR: query $domain failed: $errn\”;
return if ($err =~ /NXDOMAIN/);
}
return \’OK\’;
}
### return nothing is FAILED, other is OK
sub pingHost {
my $arg = shift();
return 1 if (ref $arg ne \’HASH\’);
my $p;
eval { $p = Net::Ping->new($arg->{\’proto\’},$DEFAULT_TIMEOUT,0) };
if ($@) {
warn \”ERR to create Net::Ping object: $@n\”;
return;
}
$p->hires();
my ($host,$duration,$hip,$rep,$ret);
### tcp/syn ping
if ($arg->{\’proto\’} eq \”syn\”) {
$p->{port_num} = $arg->{\’port\’};
$p->ping($arg->{\’host\’},$PING_TIMEOUT);
if (($host,$duration,$hip) = $p->ack()) {
printf(\”ACK Reply from $arg->{\’host\’}[%s] time=%.2f msn\”, $hip, $duration * 1000);
$ret = \’OK\’;
} else {
warn \”SYN Request for $arg->{\’host\’} timed out.n\”;
}
}
### icmp ping
else {
($rep,$duration,$hip) = $p->ping($arg->{\’host\’},$PING_TIMEOUT);
if ($rep) {
printf(\”Echo Reply from $arg->{\’host\’}[%s] time=%.2f msn\”, $hip, $duration * 1000);
$ret = \’OK\’;
}
else {
warn \”PING Request for $arg->{\’host\’} timed out.n\”;
}
}
$p->close;
undef($p);
return $ret;
}
my $ARG = { proto => \’syn\’, port => 80 };
my $host = $ARGV[0];
my $proto = $ARGV[1];
die \”Usage: $0 [icmp]n\” if (! $host);
$ARG->{\’host\’} = $host;
$ARG->{\’proto\’} = $proto if ($proto);
my $code;
if (&queryDomain($host) eq \’OK\’ and $code = &pingHost($ARG)) {
print \”$host is online !n\”;
}
else {
print \”$host is DOWN !n\”;
}
测试例子：
# ./check.host.pl 2013.jb51.net
ERR: query 2013.jb51.net failed: NXDOMAIN
2013.jb51.net is DOWN !
# ./check.host.pl www.jb51.net
ACK Reply from www.jb51.net[173.255.214.254] time=307.04 ms
www.jb51.net is online !
# ./check.host.pl jb51.net icmp
Echo Reply from jb51.net[173.255.214.254] time=205.61 ms
jb51.net is online !
# ./check.host.pl chinagfw.com icmp
PING Request for chinagfw.com timed out.
chinagfw.com is DOWN !
