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diff --git a/zk/IP_addresses.md b/zk/IP_addresses.md
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@@ -0,0 +1,33 @@
+---
+title: IP_addresses
+tags: [network, internet]
+created: Friday, August 16, 2024
+---
+
+# IP addresses
+
+## IPv4 vs IPv6
+
+IP addresses come in two formats and bit-lengths depending on which version of
+the [Internet Protocol](Internet_Layer_of_Internet_Protocol.md) is being used.
+
+- IPv4 addresses are 32-bits in length
+- IPv6 addresses are 128-bits in length
+
+The larger the bit-length, the more unique addresses that can be generated. Thus
+IPv6 can create more addresses that IPv4.
+
+This entry focuses on IPv4 addresses.
+
+## Anatomy of an IPv4 address
+
+Each of the 32 bits are divided into four groups which are each 8 bits (a byte)
+in length. Each group therefore comprises an octet and is separated by dots.
+
+The decimal number system, rather than binary is used to represent the values.
+Thus each octet comprises three decimal digits as 8-bits = 2^3.
+
+The 32 bits form two sections:
+
+- the **network prefix**
+- the **host**
diff --git a/zk/Internet_Layer_of_Internet_Protocol.md b/zk/Internet_Layer_of_Internet_Protocol.md
index c9a7541..5d08ffb 100644
--- a/zk/Internet_Layer_of_Internet_Protocol.md
+++ b/zk/Internet_Layer_of_Internet_Protocol.md
@@ -13,16 +13,16 @@ In order for the data to get from a machine on one local network to a machine on
 another local network, each machine must have a way of identifying and
 interfacing with the other.
 
-The Internet Layer utilises the Internet Protocol to determine how devices will
-be publicly identified to devices on other networks and how different devices on
-the same local network will be distinguished from outside of this network. This
-is achieved through Internet Protocol (IP) addresses.
+The Internet Layer utilises the **Internet Protocol** to determine how devices
+will be publicly identified to devices on other networks and how different
+devices on the same local network will be distinguished from outside of this
+network. This is achieved through Internet Protocol (IP) addresses.
 
 ## Packets
 
 Data is sent accross the internet between hosts as _packets_. These packets,
 when sent and received within the
-![Link Layer](Link_Layer_of_Internet_Protocol.md) on the local network, are
+[Link Layer](Link_Layer_of_Internet_Protocol.md) on the local network, are
 enclosed within a Link Layer frame (in its payload section):
 
 ![Internet Layer packet](../img/internet-layer-packet.png)
diff --git a/zk/Internet_fundamentals.md b/zk/Internet_fundamentals.md
index 88a11af..d8bd766 100644
--- a/zk/Internet_fundamentals.md
+++ b/zk/Internet_fundamentals.md
@@ -27,17 +27,15 @@ protocols. From the top:
 
 ![TCP/IP stack diagram](../img/TCP_IP.png)
 
-- The ![Link Layer](Link_Layer_of_Internet_Protocol.md) concerns communication
+- The [Link Layer](Link_Layer_of_Internet_Protocol.md) concerns communication
   between devices on the same local network. The transfer of information once it
   has been received from the internet or its transfer between devices before it
   sent out into the internet. Ethernet and WiFi are two core protocols utilised
   at this layer.
 
-- The
-  ![Internet Layer of Internet_Protocol](Internet_Layer_of_Internet_Protocol.md)
-  is concerned with communication accross networks. It is responsible for
-  identifying hosts on the inter-network by their addresses and routing data
-  from network to network.
+- The [Internet Layer](Internet_Layer_of_Internet_Protocol.md) is concerned with
+  communication accross networks. It is responsible for identifying hosts on the
+  inter-network by their addresses and routing data from network to network.
 
 - The **Transport Layer** come back to this