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Need perl regex for ip range

Posted on 2009-04-09
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I need to have a perl regex expression to match the ip range 96.6.0.0 to 96.7.255.255
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Question by:Melaleuca
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by:Adam314
ID: 24108452
I don't think you'll be able to do it with just a regex, as these are used to check strings.  Can you use any logic other than a regex?
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by:Melaleuca
ID: 24108638
I have searched the web and have found ways to match for a IP address with a Regex expression. I'm am not that great with regex and don't fully understand how the string should look. It has to be a regex because that is all websense will allow.
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ozo earned 400 total points
ID: 24108825
^96\.[67](\.(1?\d?\d|2([0-4]\d|5[0-5]))){2}$
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by:ghostdog74
ghostdog74 earned 100 total points
ID: 24113196
>>  I'm am not that great with regex and don't fully understand how the string should look

no need regular expression if you are not familiar. have you forgotten normal string comparison? sure, its lengthier than short regex, but at one look, you know what's it doing.

my $ip = "96.8.256.1";
my @list = split /\./,$ip;
if (  $list[0] == "96" && 
      ( $list[1] >= 6 && $list[1] <= 7) &&
      ( $list[2] >= 1 && $list[2] <=255) &&  
      ( $list[3] >= 1 && $list[3] <=255)    ) {
    print "ok";
}else{
    print "ip not ok";
}

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Expert Comment

by:ozo
ID: 24113510
did you want to accept 96.6.0.0 and 96.7.0.0  ?

I also note that the split and compare routine would accept things like
$ip = '96.6e0.1e1.22222e-3'
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Expert Comment

by:ghostdog74
ID: 24113911
>>I also note that the split and compare routine would accept things like
$ip = '96.6e0.1e1.22222e-3'

if that's the case, performing a check to see if its a number(integer) before doing the comparison should do it.

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Expert Comment

by:ozo
ID: 24114069
6e0 and 1e1 are integers
so is '   1   '
But that may support your point that at one look, you know what's it doing.
At one look, it may not be quite as easy to know whether or not the regex would accept any of those.
And if one wants to change the ip range 96.6.0.0 to 96.7.255.255
into an  ip range 96.6.1.1 to 96.7.255.255
it may be less obvious at one look how to adjust the regex
but Melaleuca also said that It has to be a regex because that is all websense will allow.

Another way with comparisons:
 $v = eval ($ip = "96.8.256.1");
if( ($v & 255.255.255.255) eq $v && 96.6.0.0 le $v && $v le 96.7.255.255 ){ print "ok"; }

But this can be dangerous if you have
$ip='system"logout"'; #or worse
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Expert Comment

by:ghostdog74
ID: 24114147
i do not know about websense and why it can only use regex, but if that's the case, so be it.
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