How to Find a Network IP Address
Based on OS: Windows: Start --> Type "CMD" in search field --> open command prompt --> type "ipconfig /all" --> look at and note the computers IP address and Subnet Mask Mac: Applications --> Utilities --> Terminal --> at prompt, type "ifconfig -a"...
Step-by-Step Guide
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Step 1: Based on OS: Windows: Start --> Type "CMD" in search field --> open command prompt --> type "ipconfig /all" --> look at and note the computers IP address and Subnet Mask Mac: Applications --> Utilities --> Terminal --> at prompt
Begin by determining the of subnets that are present.
This is accomplished by using your subnet mask.
The formula is: 2^n (where n = # of network bits used less the default for that range) Tip #2.
Example:
IP
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192.168.3.52; Subnet Mask
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255.255.255.128.
Default subnet mask based on first octet (192) is
255.255.255.0 (or CIDR /24) The "128" in the last octet tells us that one additional network bit is used beyond default.
Tip #3.
Plug values into formula (using CIDR).
Example: 25
- 24 =
1. 2^n = 2^1 = 2 = 2 subnets. , The first three octets of the IP will not change; leaving us with 2 Net ID's:
192.168.3.0 and
192.168.3.128.
Tip #4 By looking at the value of the fourth octet, we see that 52 falls between 0 and 127, thereby putting our IP in the first subnet with a Net ID of
192.168.3.0. , Network ID:
192.168.3.0 First Assignable IP:
192.168.3.1 Last Assignable IP:
192.168.3.126 Broadcast IP:
192.168.3.127 -
Step 2: type "ifconfig -a" --> look at and note inet address (aka IP address) and netmask (aka Subnet Mask - given in HEX (ex: 0xFFFFFF00) Conversion - Tip 1);
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Step 3: Based on your IP address and subnet mask
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Step 4: we can determine what subnet we are in
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Step 5: including the Net ID
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Step 6: Broadcast Address
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Step 7: and range of assignable IP's.
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Step 8: Now that the number of subnets has been determined (as per above example)
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Step 9: we will have to determine which of the two subnets our IP address falls into.
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Step 10: Lastly
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Step 11: note that we have established our Net ID
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Step 12: we can determine our first assignable IP
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Step 13: last assignable IP and broadcast address (Tip #5) for the example IP - 192.168.3.52; Subnet Mask 255.255.255.128.
Detailed Guide
Begin by determining the of subnets that are present.
This is accomplished by using your subnet mask.
The formula is: 2^n (where n = # of network bits used less the default for that range) Tip #2.
Example:
IP
-
192.168.3.52; Subnet Mask
-
255.255.255.128.
Default subnet mask based on first octet (192) is
255.255.255.0 (or CIDR /24) The "128" in the last octet tells us that one additional network bit is used beyond default.
Tip #3.
Plug values into formula (using CIDR).
Example: 25
- 24 =
1. 2^n = 2^1 = 2 = 2 subnets. , The first three octets of the IP will not change; leaving us with 2 Net ID's:
192.168.3.0 and
192.168.3.128.
Tip #4 By looking at the value of the fourth octet, we see that 52 falls between 0 and 127, thereby putting our IP in the first subnet with a Net ID of
192.168.3.0. , Network ID:
192.168.3.0 First Assignable IP:
192.168.3.1 Last Assignable IP:
192.168.3.126 Broadcast IP:
192.168.3.127
About the Author
Barbara Hill
Enthusiastic about teaching organization techniques through clear, step-by-step guides.
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