socket connection trouble

tablex

Hi,

I've written a simple script,that checks whether some service is up or down on a host, the "strange" thing is it works correct with all services I've tried, but the 'www' service is just always up on any host even if it doesn't exist, I'm obviously doing something wrong, but what?

Below is an example code:

<?php
$sTarget = "www.tools.ccghhgcom";

function IsHostUp($sTarget,$iPort=80,$dTimeout=30){

$rSocket = @fsockopen($sTarget,$iPort,$iErrorNr,$sErrStr,$dTimeout);
if(!$rSocket)
            {
			return("$sErrStr($iErrorNr)");
			}
fclose($rSocket);
return(true);

}

$mResult = IsHostUp(gethostbyname($sTarget));
if($mResult!==true)
{
echo"$sTarget is down $mResult";
}
else
{
echo"$sTarget is up";
}
?>

tablex

never mind... using: gethostbyname("FAKE_ADDRESS") always returns 195.85.134.2.

is this a bug or a feature 😉

sidney

no its not a bug as your function returns a string or true

a string will evaluate to true, so check if its a string

 $mResult = IsHostUp(gethostbyname($sTarget)); 
if(is_string($mResult))
{ 
echo"$sTarget is <b>down</b><br>$mResult"; 
}

check table O-1 the boolean : if($x) column
http://uk.php.net/manual/en/types.comparisons.php

tablex

if you had taken a better look:

if($mResult!==true)
{
echo"$sTarget is down $mResult";
}

"===" checks if value is the same and of the same type
"!==" the opposite

sidney

i did notice the way you where doing it and i still maintain it evaluates $mResult as true even when its a string

i drew your notice to the first table as this is how it evaluates your conditional

the better way to lay out your if else statement would be

   if($mResult===true)
{ 
echo"$sTarget is <b>up</b>";
} 
else 
{ 
 echo"$sTarget is <b>down</b><br>$mResult"; 
}

then it would give the results expected from table 3

mtmosier

Ummm... This

if($mResult===true)
{ 
echo"$sTarget is <b>up</b>";
} 
else 
{ 
 echo"$sTarget is <b>down</b><br>$mResult"; 
}

and

if($mResult!==true)
{
echo"$sTarget is <b>down</b><br>$mResult";
}
else
{
echo"$sTarget is <b>up</b>";
}

are functionally equivalent.

Oh, and just for reference gethostbyname does return the expected value (the bad domain as a string) for me, not some seemingly random ip. Might be a dns misconfiguration/"feature".

tablex

thanks a lot mtmosier it was a dns misconfig