Unable To Ping External Hosts Using In Perl Using Net::Ping - linux

Question

In Perl (5.16.3), I'm trying to use Net::Ping to test whether a remote host is available or not. I'm able to ping "internal" hosts which I know are online within my company's LAN, but I'm unable to ping "external" ones. Specifically, trying to ping 'www.google.com' fails.
My code:
#!/usr/bin/perl
use strict;
use warnings;
use Net::Ping;
my $hostname1 = 'prophet'; #internal
my $hostname2 = 'www.google.com'; #external
my $p;
my $rv1;
my $rv2;
$p = Net::Ping->new();
$rv1 = $p->ping($hostname1);
$rv2 = $p->ping($hostname2);
print "Response1: $rv1\n";
print "Response2: $rv2\n";
Yields this result:
[oracle#prophet:bin]$ ./ping_test
Response1: 1
Response2: 0
[oracle#prophet:bin]$
Even though using the (CentOS) ping utility does show that 'www.google.com' is available:
[oracle#prophet:bin]$ which ping; ping www.google.com
/usr/bin/ping
PING www.google.com (64.233.177.105) 56(84) bytes of data.
64 bytes from 64.233.177.105: icmp_seq=1 ttl=46 time=15.6 ms
64 bytes from 64.233.177.105: icmp_seq=2 ttl=46 time=15.6 ms
64 bytes from 64.233.177.105: icmp_seq=3 ttl=46 time=15.7 ms
64 bytes from 64.233.177.105: icmp_seq=4 ttl=46 time=16.5 ms
^C
--- www.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3005ms
rtt min/avg/max/mdev = 15.614/15.884/16.547/0.394 ms
[oracle#prophet:bin]$
I realize that if I do this (in my Perl program):
$p = Net::Ping->new('icmp');
Then su - root before I run the program, it'll work...
[oracle#prophet:bin]$ su root
Password:
[root#prophet:bin]# ./ping_test
Response1: 1
Response2: 1
[root#prophet:bin]#
... but, I'd like to be able to use Net::Ping (w/ icmp packets) without having to su - root. It's actually a requirement for an automation program I need to write. It seems a little crazy to me that I can run the ping (CentOS) utility as a regular user and get the expected results, but that trying to use Net::Ping as a regular user is a no-go.
Any ideas?
G

Answer 1

The ping utility works because it's setuid — it runs with root privileges, even when executed by a normal user:
-rwsr-xr-x 1 root root 44168 May 7 2014 /bin/ping
Like it or not, using ICMP inherently requires root privileges. You can't do it as a normal user.
If you want to check for connectivity, consider making a TCP connection. (Or, heck, a full HTTP request.)