Use Regular expression while adding static host list on CPPM with IP address

Aruba Employee
Aruba Employee

This article talks about adding Static Host List with IP address in form of a regular expression.

 

We can add a static host list on CPPM by navigating to Configuration » Identity » Static Host Lists.

 

 

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Tips about writing a regular expression.


IP Addresses have a particular form.

number.number.number.number

 

Where the number can be pretty much any number from 0 to 255.

Valid  :  1.2.3.4    10.10.10.10   230.245.250.131
Invalid: 1023.10.1.2    256.1.2.3    230.245.270.131


Lets note the immediate observations:

    a: 4 numbers, each separated by a single dot
    b: 3 dots in total
    c: each number can be from 1 to 3 digits in length
    d: each number can be from 0 to 255

The base solution would be

 

.*\..*\..*\..*


Improvising it we would get

[0-9]|[0-9][0-9]|[0-9][0-9][0-9]


    This means that we may have

     A single digit: [0-9]
               OR
    1 or 2 or 3 digits?

Better way to write the same would be :  [0-9]{1,3} where items with curly brackets: {min,max}


So the complete IP would be

[0-9]{1,3} \. [0-9]{1,3} \. [0-9]{1,3} \. [0-9]{1,3}

But the above solution is very generic and would allow invalid IPs like 999.999.999.999 also. This is just a base line solution for IP address.

Below is a Real Example.

Allowed IP Range is :  192.18.0.0 - 192.19.31.255


Break down of Range

192.18.
192.19.0 to 31.

and

192.19.[0-9].
192.19.1[0-9].
192.19.2[0-9].
192.19.30.
192.19.31.


Combining both we can write en expression as below.

^
192\.
 (
   18\.
    |
   19\.
      (
         [0-9]\.
         |
         1[0-9]\.
         |
         2[0-9]\.
         |
         30\.
         |
         31\.
      )
  )



We can remove a few "\" and re-write the expression as shown below.

^192\.
  (
     18\.|
     19\.
        (
          [0-9]|1[0-9]|2[0-9]|30|31
         )
         \.
   )

 

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Revision #:
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Last update:
‎07-11-2014 03:45 PM
Updated by:
 
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