1. IP Functions
Introduction
ipfx@rajivbhardwaj.com

2. Version Details
Version Date Edited by Section/s Comments
1.0 22-02-2012 Rajiv Bhardwaj All First Draft
1.1 19-06-2012 Rajiv Bhardwaj All Added four more functions, Removed “RB_” prefix from function
names

3. Purpose:
Provide Introduction to Excel based IP functions created by me.
Provide Instructions for Installation and operating the IP Functions .
Scope:
Provide Excel based IP functions for easier IP Planning.
Provide Excel based IP functions for creating automated templates.

4. Motivation
After I got tired with manually modifying IP address in excel, I decided to give a try
to creating some kind of formulae.
I got some success with inbuilt “left” & “right” functions. e.g. by using something
like this to increment the IP address at position A1.
LEFT(A1,FIND(“.”,A1,FIND(“.”,A1,FIND(“.”,A1,1)+1)+1))&RIGHT(A1,LEN(A1)-FIND_
(“.”,A1,FIND(“.”,A1,FIND(“.”,A1,1)+1)+1))+1

5. Limitation of using Formulae
But soon it became quite cumbersome because of 3 reasons.
1. Every time I wanted to use this formula I had to change the reference cell ID “A1″
manually. It defeated the original purpose of automation.
2. It didn’t work well for changing the Class A or B IP Subnets i.e. updating any of
the first three “parts” of IP address.
3. As I started working on some IP hungry nodes. Handling of huge number of IPs
became almost impossible by this method.
To overcome these limitations I tried to create VBA based functions which are
easier to use and provide more functionalities.
I didn’t have much experience with macros and VBA, but still was able to create a
set of working functions.

6. IP Functions
I have complied all the IP address related functions in Add-in format. This way it is
easy to share all the functions without much effort on the end user part.
Although, .xla format is not fully portable as excel sheets created by one user
cannot be used by another user without updating the links. But it’s the easiest way
to transfer reusable functions.
This Add-in RBIPFx include following functions in present version (0.3).
1. IP_Bits2Mask
2. IP_ErrChk
3. IP_Hosts
4. IP_IP2Mbits
5. IP_Mod
6. IP_NextSub

7. IP Functions
7. IP_Bcast
8. IP_Count
9. IP_IsExist
10. IP_Mask2Bits
11. IP_Subnet

8. INSTALLING EXCEL ADD-IN

9. Installing RBIPFx Addin -I
1. First move the add-in file (“.xla”) to “C:Addins” folder
2. For Excel 2003 or older, go to addins menu by selecting Tools->Add-ins.
3. Then choose the desired add-in from list. Add-in will appear in the list if you
have copied it to the right Add-in folder as described in step 1.
4. If Add-in is not displayed in the list then you can use the browse button to locate
the Add-in File.

10. Installing RBIPFx Addin -II
For Office 2007 or later:
1. First move the add-in file (“.xla”) to “C:Addins” folder
2. Click on the Office button in top left corner.
3. Then choose excel options.

11. Installing RBIPFx Addin -III
4. Select “Add-ins” , choose Manage “Excel Add-ins” and click Go.
5. Then choose the RBIPFx.xla add-in from list and click OK. Add-in will appear in
the list if you have copied it to the right Add-in folder as described in step 1.

12. Installing RBIPFx Addin -IV
6. If Add-in is not displayed in the list then you can use the browse button to locate
the Add-in File.
7. If Add-in is correctly installed then it may show a relevant message.
8. Once installation is complete then you can see the “compatible” add-ins in the
Add-ins tab of office ribbon. (Optional)

13. FUNCTION DESCRIPTION

14. IP_Mod: IP Modification Function
IP_Mod: This is the primary function of RBIPFx Excel Add-in. It modifies the IP
addresses.
Syntax: RB_Mod_IP( IP address, optional Step, Optional Part)
Parameters:
IP Address: As the name suggest is IPV4 IP address which you want to modify.
Step: It is the number by which you want to increment or decrement the given IP
address. It is optional and default value of this parameter is 1.
Part: It is the part of IP address you want to modify. As IPv4 address as 4 parts
separated by “.”.
i.e For IP 10.11.12.13, Part 1 =10, part 2=11, Part3 =12 & Part4 =13.
It is also optional parameter & default value of this part is 4. i.e. last part (Class C
subnet)

15. IP_Mod: IP Modification Function - Usage
USAGE: Following are some of the ways, this function can be used.
i) You can increment the IP by one just by using the IP address parameter. i.e.
IP_Mod(“10.11.12.13″,1) will give 10.11.12.14.

16. IP_Mod: IP Modification Function - Usage
As I have set the value of Step to be 1 by default so IP_Mod(“10.11.12.13″) will also
do.

17. IP_Mod: IP Modification Function - Usage
Dragging this function in excel column will give you a series of IPs.

18. IP_Mod: IP Modification Function - Usage
But if you want to increment the IP with bigger value then you need to use the
parameter STEP.
e.g
IP_Mod(“10.11.12.13″, 10) will give you 10.11.12.23.

19. IP_Mod: IP Modification Function - CIDR
IP address with subnet maskbits (e.g. xx.xx.xx.xx/24) is also used in the IP domain
This function can handle that too. It automatically detects the subnet mask
separator (“/”) and uses the same format for output.
e.g
IP_Mod(“10.11.12.13/24″,10,3) will give you 10.11.22.13/24 as output.

20. IP_Mod: IP Modification Function - Decrement
If you want to decrement an IP address instead of incrementing then you can do
that too by just giving a negative Step Value.
e.g IP_Mod(10.11.12.13, -5) will give 10.11.12.8

21. IP_Mod: IP Modification Function - Error Handling
Error Handling: It can handle basic error situations.
if you input a step value more than 255 or less than -255. Function will return an
error.
e.g.
IP_Mod(10.11.12.13, 258) will give “#NUM” as return. This error is inline with basic
excel errors as it signifies that wrong value of number is being used.

22. IP_Mod: IP Modification Function - Error Handling
I initially had pop-up message for such situations but it becomes quite irritating if
we have a large sheet full of IP addresses.
One more situation which I have captured is that sometimes input is well within
range but the resultant IP is out of range. It also generates error in such situation.
e.g. IP_Mod(10.11.12.13, 245) will give “#NUM” error as resultant IP 10.11.12.258
is not the valid one. For me this error functionality is a real life saver as I tend to
forget this “255″ limit.

23. IP_NextSub: Next Subnet Function
This function calculates next IP subnet. Subnet mask is mandatory parameter for
this function.
This function can also work with CIDR notation.
If both CIDR notation and Maskbit parameter are given, maskbit parameter is given
higher priority.

24. IP_Bits2Mask
Converts Bits to Subnet Mask

25. IP_ErrChk
Function checks if IP Address is valid or not

26. IP_Hosts
Function calculates number of hosts from mask bits.
It automatically deducts 2 IPs from the number of hosts to compensate for network
address & broadcast address

27. IP_IP2Mbits
This function calculates the Mask Bits (Subnet Mask) for the required number of
IPs.
e.g. If we require 11 IPs then a IP subnet with subnet mask of /28 is required.

28. IP_Subnet
This function calculates the Subnet (Network Address) for the given IP
e.g. Subnet for 10.1.1.99/28 is calculated to be 10.1.1.96.

29. IP_Bcast
This function calculates the Broadcast address for given IP .
e.g. Broadcast address for 10.1.1.99/28 is 10.1.1.111

30. IP_Mask2Bits
This function calculates the Mask Bits from the Subnet mask in “x.x.x.x” format.
e.g. Subnet mask 255.255.255.240 is equivalent to 28 maskbits i.e. /28.

31. IP_IsExist
This is a boolean function to check if one IP exists in an IP range (Subnet). It also
checks if an IP subnet overlaps with other IP subnet.
First argument is the IP range, in which the given IP (subnet) will be checked
Second argument is the IP (Subnet) to be checked
e.g. We can check if 10.1.1.112 exists with in 10.1.1.96/28.

32. IP_Count
This function counts the occurrence of an IP address in a given range of IP network
addresses (subnets). It can be used to check the overlapping subnets in an IP Plan
First argument is the IP range, in which the given IP (subnet) will be checked
Second argument is the IP (Subnet) to be checked

33. Thank You