====== What is a CDN (Content Delivery Network)? ======
A Content Delivery Network (CDN) is a system of distributed servers located around the world that work together to deliver web content to users more efficiently.
===== Purpose =====
The main goal of a CDN is to reduce latency and improve the speed, reliability, and security of content delivery. Instead of serving content from a single origin server, a CDN caches and delivers static assets (like images, stylesheets, scripts, and videos) from servers that are geographically closer to the user.
===== How It Works =====
When a user accesses a website:
  * The CDN determines the closest edge server to the user.
  * Static content is served from that nearby server.
  * This reduces the time it takes for the content to load and minimizes bandwidth usage on the origin server.
===== Benefits =====
  * Faster load times for users worldwide
  * Reduced server load and bandwidth usage
  * Improved availability during traffic spikes
  * Enhanced security features like DDoS protection and secure SSL delivery
===== Example =====
If your website is hosted in Germany and a visitor from Japan accesses it, the CDN will serve cached content from a server in Japan, making the site load much faster for that user.
===== Common CDN Providers =====
  * Cloudflare
  * Akamai
  * Fastly
  * BunnyCDN
  * Amazon CloudFront
====== Benefits of a CDN in Second Life ======
Second Life uses a Content Delivery Network (CDN) to distribute texture and mesh data more efficiently across the globe. This shift from simulator-based delivery to CDN-based delivery has brought several key improvements to the platform.
===== 🚀 Performance Improvements =====
  * Faster loading of textures and meshes
  * Assets like avatar skins, clothing, and environment textures now load significantly faster, especially in crowded regions.
  * Quicker region crossings and teleports
  * Reduced load on simulator servers means smoother transitions between areas.
  * Reduced “fuzzy” or “cloudy” avatars
  * Avatars appear fully rendered more quickly, improving visual quality and immersion.
===== 📉 Reduced Server Load =====
  * CDN offloads asset delivery from simulator servers, freeing up resources for physics, scripting, and interaction.
  * High HTTP load conditions on servers have dropped dramatically since the CDN rollout.
===== 🌍 Global Reach =====
  * Users outside North America benefit even more, with over 50% faster download times for textures and meshes.
  * CDN edge servers deliver content from locations closer to the user, reducing latency.
===== 🔧 Technical Stability =====
• 	Improved resilience during traffic spikes or outages.
• 	Faster recovery from load-related issues thanks to CDN redundancy and optimizations.
===== ✅ Summary =====
The integration of CDN technology into Second Life has:
• 	Enhanced user experience through faster asset loading
• 	Reduced strain on core infrastructure
• 	Enabled more scalable and reliable virtual environments

====== Squid Proxy: Monitoring Logs and Editing Configuration ======
This guide explains how to monitor Squid proxy logs in real time, edit its configuration file, and includes a sample shell script for setting up a test directory.
===== 📄 Live Log Monitoring =====
To monitor Squid activity in real time, use the following command:
<code>
sudo tail -f /var/log/squid/access.log /var/log/squid/cache.log
</code>

This will continuously display new entries from:
• 	access.log – records client requests
• 	cache.log – logs cache behavior and errors
===== ⚙️ Editing the Configuration File =====
To edit Squid’s main configuration file, run:
<code>sudo nano /etc/squid/squid.conf</code>

Example config:

<code>
http_port 192.168.0.43:1234 #the machine this is running on
# http_port 127.0.0.1:1234

cache_dir aufs /var/spool/squid/slcdn-cache 100000 16 256
cache_mem 1024 MB
maximum_object_size 1024 MB
maximum_object_size_in_memory 50 MB
minimum_object_size 0 KB

cache_log /var/log/squid/cache.log
access_log daemon:/var/log/squid/access.log
cache_store_log /var/log/squid/store.log

acl localnet src 192.168.0.0/24
http_access allow localnet
http_access deny all

cache allow all
refresh_pattern . 43200 100% 43200

range_offset_limit -1
collapsed_forwarding on
</code>
===== 📁 Log Paths in Configuration =====
Inside , you can define the paths for Squid’s log files:

• 	: logs cache-related events
• 	: logs client access (via daemon)
• 	: logs stored objects
===== 🧪 Example: Shell Script for Setup =====
Here’s a simple Bash script to create a test directory:

tTo run the script run the command:
<code>
./SLEdgeCDN.sh
</code>

[[https://mond-keks.de/downloads/SLEdgeCDN.sh|SLEdgeCDN.sh]]

<file SLEdgeCDN.sh>
#!/bin/bash
set -e

BASE="$HOME/Desktop/SL_CDN_TEST"

echo "=== SL CDN Installer ==="

# install squid if not installed
if ! command -v squid >/dev/null 2>&1; then
  if [ -f /etc/debian_version ]; then
    sudo apt update && sudo apt install -y squid
  elif [ -f /etc/fedora-release ]; then
    sudo dnf install -y squid
  elif [ -f /etc/arch-release ]; then
    sudo pacman -Sy --noconfirm squid
  else
    echo "Your distro isn’t supported. Install squid manually."
    exit 1
  fi
fi

# backup old squid.conf
sudo cp /etc/squid/squid.conf /etc/squid/squid.conf.bak.$(date +%s) || true

# write new config
sudo tee /etc/squid/squid.conf >/dev/null <<EOF
http_port 127.0.0.1:1234

cache_dir aufs /var/spool/squid/slcdn-cache 100000 16 256
cache_mem 1024 MB
maximum_object_size 1024 MB
maximum_object_size_in_memory 50 MB
minimum_object_size 0 KB

cache_log /var/log/squid/cache.log
access_log daemon:/var/log/squid/access.log
cache_store_log /var/log/squid/store.log

acl localnet src 127.0.0.1/32
http_access allow localnet
http_access deny all

cache allow all
refresh_pattern . 43200 100% 43200

range_offset_limit -1
collapsed_forwarding on
EOF

# make cache and log dirs
sudo mkdir -p /var/spool/squid/slcdn-cache /var/log/squid
sudo chown -R proxy:proxy /var/spool/squid /var/log/squid
sudo squid -z

# restart squid
sudo systemctl restart squid

# reset desktop control folder
rm -rf "$BASE"
mkdir -p "$BASE"

# main control script
cat > "$BASE/slcdn.sh" <<'EOS'
#!/bin/bash
LOG=$HOME/Desktop/SL_CDN_TEST/proxy.log
start()   { echo "Starting Squid..." | tee -a "$LOG"; sudo systemctl start squid; }
stop()    { echo "Stopping Squid..." | tee -a "$LOG"; sudo systemctl stop squid; sudo killall -9 squid 2>/dev/null || true; sudo rm -f /run/squid.pid; }
restart() { echo "Restarting Squid..." | tee -a "$LOG"; stop; sudo squid -z || true; start; }
status()  { echo "Squid status:" | tee -a "$LOG"; sudo systemctl status squid --no-pager -l; }
case "$1" in start|stop|restart|status) "$1";; *) echo "Usage: $0 {start|stop|restart|status}";; esac
EOS
chmod +x "$BASE/slcdn.sh"

# clear cache script
cat > "$BASE/slcdn-clear.sh" <<'EOS'
#!/bin/bash
echo "Clearing Squid cache..."
sudo systemctl stop squid || true
sudo killall -9 squid 2>/dev/null || true
sudo rm -f /run/squid.pid
sudo rm -rf /var/spool/squid/slcdn-cache
sudo mkdir -p /var/spool/squid/slcdn-cache
sudo chown -R proxy:proxy /var/spool/squid/slcdn-cache
sudo squid -z
echo "Cache cleared. Restart Squid to refill."
EOS
chmod +x "$BASE/slcdn-clear.sh"

# desktop shortcuts
make_launcher () {
  local name="$1" cmd="$2" term="$3"
  cat > "$BASE/SLCDN-$name.desktop" <<EOD
[Desktop Entry]
Name=SL CDN $name
Exec=$cmd
Icon=utilities-terminal
Terminal=$term
Type=Application
EOD
  chmod +x "$BASE/SLCDN-$name.desktop"
}

make_launcher "Start"   "$BASE/slcdn.sh start" true
make_launcher "Stop"    "$BASE/slcdn.sh stop" true
make_launcher "Restart" "$BASE/slcdn.sh restart" true
make_launcher "Status"  "$BASE/slcdn.sh status" true
make_launcher "Clear"   "$BASE/slcdn-clear.sh" true
make_launcher "Cache"   "xdg-open /var/spool/squid/slcdn-cache" false
make_launcher "Debug"   "gnome-terminal -- bash -c \"sudo tail -f /var/log/squid/access.log\"" false

echo "Done. Set Firestorm proxy to 127.0.0.1 port 1234"
</file>

This script creates a folder on the user’s desktop and can be extended for further setup tasks.
===== ⚙️ Firestorm settings =====
{{:settingsproxy.png|}}