SPUG: I must be missing something with Net::Ping
Mark Yocom
myocom at microsoft.com
Mon Oct 8 19:53:03 CDT 2001
Maybe it's just me, but when I do 'perldoc Net::Ping', it says that the
default protocol is UDP, not ICMP.
Do you get the same results if you explicitly set the protocol used?
my $p = Net::Ping->new('icmp');
> -----Original Message-----
> From: Alyssa Harding [mailto:alyssa at atuin.net]
> Sent: Monday, October 08, 2001 5:07 PM
> To: SPUG
> Subject: SPUG: I must be missing something with Net::Ping
>
>
> Hi List,
>
> Maybe someone else can look at this and tell me I'm missing something
> simple.
>
> I've got a script which runs on a server outside the firewall
> and pings
> certain servers. i'm using Net::Ping to do the pinging but
> I'm coming
> up with wierd results.
>
> use Net::Ping;
>
> my $isp = '<ip address of isp router>';
> my $outside='www.yahoo.com';
>
> my $p = Net::Ping->new(); # by default uses icmp protocol
>
> if($p->ping($isp)) {
> print "isp reached\n";
> } else {
> print "isp not reached\n";
> }
>
> if( $p->ping($outside)) {
> print "outside reached\n";
> } else {
> print "outside not reached\n";
> }
>
> $p->close();
>
> When I run the script I get the following output:
> isp reached
> outside not reached
>
> In other words, I can ping our ISP's router but I can't ping
> yahoo.com.
> So I tried on the command line (HPUX v10.20 seems to have the
> same ping
> as my Red Hat 7.1 box with different option flags - they are
> functionally the same though):
> ping <isp's router>
> and got a response just fine - good. I expected that. So I tried:
> ping www.yahoo.com
> and got a response just fine - hmmmm.
>
> Why won't the script do what the command line does when they are both
> using the same protocol to do the same thing? Traceroute shows the
> first hop being to the ISP's router and then about 18 more
> hops and #20
> is yahoo.
>
> Any ideas?
>
> A.
> --
> Alyssa Harding
> ----------------------------------------------------------------
> "Why's it called Ming?" said the Archchancellor, on cue.
> The Bursar tapped the pot. It went *ming*.
> -- Discworld archeology revealed
> (Terry Pratchett, Moving Pictures)
>
>
>
>
>
>
>
>
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