Скачать или смотреть Day 14 [PROJECT ONE] | Local Multi-Host Virtual Network Lab

In this hands-on DevOps networking project, you'll learn to simulate a complete cloud-style network on your own
machine using only Linux tools. This is perfect for anyone learning Linux, DevOps, Networking, or
preparing for interviews.

What You'll Build:
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3 virtual hosts (namespaces) with their own IPs
A virtual switch (bridge) that connects them
A firewall that blocks selected traffic
Manual DNS resolution (via /etc/hosts)

Project Architecture:
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[host1] 10.0.0.2
[host2] 10.0.0.3
[host3] 10.0.0.4
Connected via: v-net0 (Linux bridge)

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ACTION PLAN - Copy & Paste These Commands to Follow Along

Create network namespaces (virtual hosts)
sudo ip netns add host1
sudo ip netns add host2
sudo ip netns add host3

Create a virtual switch
sudo ip link add v-net0 type bridge
sudo ip link set v-net0 up

Create veth pairs (cables)
for i in 1 2 3; do
sudo ip link add veth$i type veth peer name veth${i}br
done

Connect hosts to the bridge
sudo ip link set veth1 netns host1
sudo ip link set veth2 netns host2
sudo ip link set veth3 netns host3
sudo ip link set veth1br master v-net0
sudo ip link set veth2br master v-net0
sudo ip link set veth3br master v-net0
sudo ip link set veth1br up
sudo ip link set veth2br up
sudo ip link set veth3br up

Assign IP addresses to each host
sudo ip netns exec host1 ip addr add 10.0.0.2/24 dev veth1
sudo ip netns exec host2 ip addr add 10.0.0.3/24 dev veth2
sudo ip netns exec host3 ip addr add 10.0.0.4/24 dev veth3

Enable interfaces
for i in 1 2 3; do
sudo ip netns exec host$i ip link set lo up
sudo ip netns exec host$i ip link set veth$i up
done

Test connectivity
sudo ip netns exec host1 ping -c 2 10.0.0.3
sudo ip netns exec host1 ping -c 2 10.0.0.4

Add a firewall rule to block host1 from pinging host3
sudo ip netns exec host3 iptables -A INPUT -s 10.0.0.2 -p icmp -j DROP

Re-test
sudo ip netns exec host1 ping -c 2 10.0.0.4 # Should fail
sudo ip netns exec host2 ping -c 2 10.0.0.4 # Should succeed

Simulate DNS entry
sudo ip netns exec host2 bash -c "echo '10.0.0.4 app.local' /etc/hosts"
sudo ip netns exec host2 ping app.local

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What You Learned:
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Linux namespaces as virtual hosts
Virtual Ethernet cables (veth pairs)
Bridges to simulate switches
Manual IP addressing and subnets
Basic Linux firewall with iptables
Simulated DNS with /etc/hosts

Why Follow This Series?
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Real-world DevOps skills (hands-on, not just theory)
Beginner-friendly explanations (even non-coders can follow)
Daily uploads with scripts + breakdowns
No fluff — just daily progress and real learning

🔔 Subscribe for:
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Connect With Me
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LinkedIn: www.linkedin.com/in/chukwuebuka-anunukem
YouTube:    / @techdotsam  
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