How to fix W: Failed to fetch URL Connection timed out in APT

First, verify that your system has basic network connectivity:

# Test connectivity to a public DNS
ping -c 3 8.8.8.8

# Test connectivity to a major site
ping -c 3 google.com

# Test HTTPS connectivity to a repository
curl -v https://archive.ubuntu.com/ubuntu/dists/jammy/Release

If these basic tests fail, the issue is with your network connection rather than APT specifically.

Remove corrupted cache files that might be causing fetch failures:

# Clean APT cache
sudo apt clean

# Remove partial package lists
sudo rm -rf /var/lib/apt/lists/*
sudo mkdir -p /var/lib/apt/lists/partial

# Refresh package lists
sudo apt update

The apt clean command deletes cached packages that may be incomplete or corrupted. Removing the entire lists directory forces APT to re-fetch all metadata from scratch.

The default mirror may be slow or geographically distant. Select a mirror closer to your location:

# Edit sources.list
sudo nano /etc/apt/sources.list

Replace the mirror domain with a faster alternative. For example, if using Ubuntu:

- Change archive.ubuntu.com to your country code mirror: us.archive.ubuntu.com, eu.archive.ubuntu.com, etc.
- Or try mirror.example.com from your ISP or local mirror service

For Debian, check https://www.debian.org/mirror/list for nearby mirrors.

Save and try updating:

sudo apt update

If you're unsure which mirror to choose, test connectivity first:

# Test a specific mirror
curl -I https://us.archive.ubuntu.com/ubuntu/

Configure APT to wait longer before timing out connections:

# Create a timeout configuration
sudo nano /etc/apt/apt.conf.d/99timeout

Add these lines to increase timeout values:

Acquire::http::Timeout "300";
Acquire::https::Timeout "300";
Acquire::ftp::Timeout "300";
Acquire::Retries "3";

These settings give APT 5 minutes (300 seconds) to establish connections and retry up to 3 times. Save and test:

sudo apt update

Adjust the timeout value (in seconds) based on your network speed. For slow connections, 600 seconds (10 minutes) may be appropriate.

Slow or unreliable DNS can cause timeout errors. Configure faster DNS servers:

# Edit resolv.conf
sudo nano /etc/resolv.conf

Replace the nameserver entries with public DNS servers:

nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 1.1.1.1
nameserver 1.0.0.1

To make this permanent (on systemd systems):

# Use systemd-resolved for DNS
sudo nano /etc/systemd/resolved.conf

Add:

DNS=8.8.8.8 8.8.4.4 1.1.1.1 1.0.0.1
FallbackDNS=8.8.8.8 1.1.1.1

Restart systemd-resolved:

sudo systemctl restart systemd-resolved
sudo apt update

In some environments, IPv6 connectivity is broken or slower than IPv4. Force APT to use only IPv4:

# One-time IPv4-only update
sudo apt -o Acquire::ForceIPv4=true update

To make this permanent:

# Create APT configuration
sudo nano /etc/apt/apt.conf.d/99force-ipv4

Add:

Acquire::ForceIPv4 "true";

Save and test:

sudo apt update

If you're behind a corporate firewall or proxy, ensure APT can connect:

# Test connection to repository directly
telnet archive.ubuntu.com 80

# Or use curl with verbose output
curl -v http://archive.ubuntu.com/ubuntu/dists/jammy/Release

If connections are blocked, configure your proxy:

# Create proxy configuration
sudo nano /etc/apt/apt.conf.d/99proxy

Add your proxy settings:

Acquire::http::Proxy "http://proxy.example.com:8080";
Acquire::https::Proxy "http://proxy.example.com:8080";

Then test:

sudo apt update

For Authenticated proxies, use:

Acquire::http::Proxy "http://username:[email protected]:8080";

Check that your sources.list contains valid repository URLs that haven't been deprecated:

# View current sources
cat /etc/apt/sources.list
ls -la /etc/apt/sources.list.d/

Look for:
- Outdated domain names (e.g., old Ubuntu release mirrors)
- Typos in URLs
- Repositories that no longer exist

For Ubuntu LTS releases that have reached end-of-life, archive mirrors may be required:

# For end-of-life Ubuntu releases
sudo sed -i 's/archive.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list
sudo sed -i 's/security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list

sudo apt update

For currently supported releases, verify you're using the correct mirror URLs from the official Ubuntu or Debian mirror lists.

Enable verbose logging to see exactly where the timeout is occurring:

# Run apt update with debug output
sudo apt update -V

# Or with even more verbose output
sudo apt -o Debug::Acquire::http=true update

The verbose output shows:
- Which specific URLs are timing out
- How long each connection attempt takes
- Which mirrors succeed and which fail

This helps identify if the issue is with a specific mirror or all mirrors. If only one mirror times out while others work, consider removing that mirror from your sources.list.