Understanding IP Addressing and Network Concepts – A Simple Breakdown
In this blog, I’ve summarized some essential networking concepts I’ve recently explored. These notes are not only for personal reference but also might help others trying to understand how IP addresses, NAT, and mobile data routing actually work.
1. IP Address – The Basics
An IP address is like the postal address for your device on a network. IPv4 format looks like 192.168.1.1 – four sets of numbers (0–255) separated by dots.
You might wonder, “Why does it look longer than 4 digits?” That’s because each segment is a separate number, not a single multi-digit value.
2. NAT – Network Address Translation
NAT allows multiple devices on a private network to access the internet using one public IP. It works by translating private IPs to a public one before data goes out.
Example: At home, your phone and laptop can browse the web through a single internet connection – that’s NAT working behind the scenes.
3. CGNAT – Carrier-Grade NAT
Mobile networks use CGNAT. Your phone gets a private IP from the carrier, and the carrier’s core network maps it to a shared public IP.
4. DNS and URL vs IP
DNS translates domain names to IPs. When you type google.com, DNS finds its IP and connects you.
Some sites allow access via IP, others don’t – they may block direct IP access or depend on domain-based SSL.
Example: try this into browser http://216.58.214.206 (Google’s IP) directly – it worked right (may not work because of firewall).
5. Public vs Private IPs
Private IPs (e.g., 192.168.x.x) are used inside networks. Public IPs are globally unique and assigned by ISPs.
Terms I Clarified:
- LAN: Local Area Network
- WAN: Wide Area Network
- ISP: Internet Service Provider
- NAT: Explained above
6. IP in Mobile Networks
Mobile networks assign private IPs to users and use CGNAT to handle internet traffic.
Question I Had: “What does it mean when a public IP is shared?” Answer: Many users are mapped to the same public IP via CGNAT.
7. Do Cell Towers Assign IPs?
Not directly. Cell towers connect to the carrier’s core network, which assigns a private IP to your device.
8. What is a Carrier Network?
A carrier network includes:
- Cell towers
- Core routers/switches
- NAT systems
- Backhaul links
- Internet gateways
It manages your connection from the cell tower to the web.
9. How Mobile Data is Routed
Step-by-step:
- Your phone sends a request
- Reaches cell tower
- Goes through core network and NAT
- Hits the internet/server
- Response comes back the same route
10. Dynamic IP Address
Most home and mobile users get dynamic IPs via DHCP. It changes over time and is easier to manage for ISPs.
Pros:
- Simple to allocate
- Offers better privacy
Cons:
- Not good for self-hosted servers
- IP may change frequently
That’s the summary so far. Next up, I’ll may be explore Static IPs and how DHCP works internally. May be [probably will forget to do so ]