How to Install Siege on Debian

Siege is an HTTP load testing and benchmarking utility that simulates multiple users accessing your web server simultaneously. Whether you need to stress-test a new deployment, measure response times under load, or identify performance bottlenecks before going live, Siege provides the metrics you need. This tool works with any HTTP server, including Apache and Nginx installations. By the end of this guide, you will have Siege installed and configured on Debian, with practical examples for testing web applications.

Contents hide

1 Choose Your Siege Installation Method

2 Install Siege on Debian via APT

3 Install Siege on Debian via Source Compilation

4 Configure Siege

5 Use Siege for Load Testing

6 Update Siege

7 Troubleshoot Common Issues

8 Remove Siege

9 Conclusion

Choose Your Siege Installation Method

Debian offers Siege through its default repositories, while source compilation provides access to the latest features. The following table compares both approaches to help you choose:

Method	Channel	Version	Updates	Best For
APT Package Manager	Debian Repos	Distribution default	Automatic via apt upgrade	Most users who prefer stability and easy maintenance
Source Compilation	JoeDog Downloads	Latest stable	Manual recompilation required	Users who need the newest features or custom build options

For most users, the APT method is recommended because it integrates with your system’s package management, receives security updates automatically, and requires no compilation. Choose source compilation only if you specifically need features unavailable in the repository version.

This guide covers Debian 13 (Trixie), Debian 12 (Bookworm), and Debian 11 (Bullseye). The APT package version varies by release: Debian 13 includes Siege 4.1.6, while Debian 11 and 12 provide version 4.0.7. Commands work identically across all supported releases unless noted otherwise.

Install Siege on Debian via APT

Step 1: Update Package Lists

Before installing any software, refresh your package lists to ensure you receive the latest available version from Debian’s repositories:

sudo apt update

Step 2: Install Siege

Since Siege is available in Debian’s default repositories, installation requires just a single command:

sudo apt install siege

APT automatically resolves dependencies and configures Siege for immediate use. Once installation completes, Siege creates a default configuration file in your home directory.

Step 3: Verify the Installation

Next, confirm that Siege installed correctly by checking the version:

siege --version

Expected output on Debian 13:

SIEGE 4.1.6

Copyright (C) 2023 by Jeffrey Fulmer, et al.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.

On Debian 11 and 12, the version displays as 4.0.7 with a 2018 copyright year. However, both versions function identically for most testing scenarios.

Install Siege on Debian via Source Compilation

Alternatively, compiling Siege from source provides access to the latest version (currently 4.1.7) and allows custom build options. This method requires installing development tools and libraries first.

Step 1: Install Build Dependencies

First, install the required development packages for compiling Siege:

sudo apt update
sudo apt install build-essential libssl-dev zlib1g-dev wget

These packages provide the C compiler (build-essential), SSL/TLS support (libssl-dev), compression handling (zlib1g-dev), and file downloading (wget).

Step 2: Download the Source Archive

Next, download the latest Siege source code from the official JoeDog server:

cd ~
wget https://download.joedog.org/siege/siege-latest.tar.gz

The siege-latest.tar.gz file always points to the most recent stable release. At the time of writing, this is version 4.1.7.

Step 3: Extract and Enter the Source Directory

Then, extract the downloaded archive and navigate into the source directory:

tar -xzf siege-latest.tar.gz
cd siege-*/

The wildcard pattern siege-*/ matches any version directory, so this command works regardless of the specific version you downloaded.

Step 4: Configure the Build

Now, run the configure script to detect your system’s capabilities and prepare the build environment:

./configure

The configure script detects your compiler and libraries automatically. After processing completes, you should see a success message:

checking for OpenSSL version... >= 0.9.8 (appropriate flag set)
checking for ZLIB version... checking for inline... inline
configure: creating ./config.status
config.status: creating Makefile
config.status: creating src/Makefile
config.status: creating include/config.h
config.status: executing depfiles commands

--------------------------------------------------------
Configuration is complete

Run the following commands to complete the installation:
  make 
  make install

For complete documentation:        http://www.joedog.org
--------------------------------------------------------

This output confirms the build system detected OpenSSL and zlib. If configuration fails, verify that libssl-dev and zlib1g-dev are installed.

Step 5: Compile and Install

Finally, compile the source code and install Siege. You have two options depending on your access level:

System-wide Installation (requires sudo)

To install Siege for all users on the system:

make
sudo make install

This installs Siege to /usr/local/bin/, making it available to all users on the system.

User-local Installation (no sudo required)

If you do not have root access or prefer to keep Siege in your home directory, configure with a local prefix instead. First, go back and reconfigure:

./configure --prefix=$HOME/.local

Then compile and install without sudo:

make
make install

This installs Siege to ~/.local/bin/. To use it, ensure this directory is in your PATH by adding the following to your ~/.bashrc or ~/.profile:

export PATH="$HOME/.local/bin:$PATH"

After adding this line, reload your shell configuration:

source ~/.bashrc

Step 6: Verify the Source Installation

After installation completes, confirm the source-compiled version is accessible:

siege --version

Expected output:

SIEGE 4.1.7

Copyright (C) 2024 by Jeffrey Fulmer, et al.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.

Configure Siege

Siege stores its configuration in ~/.siege/siege.conf, which it creates automatically on first run. To view the current configuration, run:

siege -C

This command displays all active settings. For APT installations, you should see output similar to:

CURRENT  SIEGE  CONFIGURATION
Mozilla/5.0 (pc-x86_64-linux-gnu) Siege/4.1.6
Edit the resource file to change the settings.
----------------------------------------------
version:                        4.1.6
verbose:                        true
color:                          true
quiet:                          false
protocol:                       HTTP/1.1
concurrent users:               25
time to run:                    n/a
socket timeout:                 30
delay:                          0.000 sec
logging:                        false
log file:                       /var/log/siege.log
resource file:                  /home/username/.siege/siege.conf

Source-compiled installations show a log path of /usr/local/var/log/siege.log instead. Both installation methods store user settings in ~/.siege/siege.conf.

Common Configuration Options

To customize Siege’s behavior, edit the configuration file:

nano ~/.siege/siege.conf

The following are key settings to consider:

concurrent

Default number of simulated users
Default: 25
Increase for higher load tests, but monitor your client machine’s resources

delay

Random delay (in seconds) between each user’s requests
Default: 0 (no delay)
Set to 1-5 for more realistic user simulation

timeout

Socket connection timeout in seconds
Default: 30
Increase if testing slow applications

logging

Enable persistent logging of test results
Default: false
Set to true for tracking performance over time

Use Siege for Load Testing

Siege provides several testing modes for different scenarios. The following examples demonstrate common use cases, along with expected output.

Basic Load Test

To start, the simplest test sends requests from the default 25 concurrent users until you stop it with Ctrl+C:

siege https://example.com

When you press Ctrl+C, the test stops and displays the results:

Lifting the server siege...
Transactions:                   1250 hits
Availability:                 100.00 %
Elapsed time:                  10.25 secs
Data transferred:               1.45 MB
Response time:                  0.20 secs
Transaction rate:             121.95 trans/sec
Throughput:                     0.14 MB/sec
Concurrency:                   24.39
Successful transactions:        1250
Failed transactions:               0
Longest transaction:            0.85
Shortest transaction:           0.08

Timed Test with Specific User Count

For more controlled testing, you can specify the number of concurrent users with -c and the test duration with -t:

siege -c 50 -t 1M https://example.com

In this example, the command simulates 50 concurrent users for 1 minute. Note that the time modifier accepts S (seconds), M (minutes), or H (hours).

Benchmark Mode

When you need maximum throughput, benchmark mode removes all delays between requests, thereby generating maximum load on the target server:

siege -b -c 100 -t 30S https://example.com

Here, the -b flag enables benchmark mode. You can use this to find your server’s maximum capacity; however, be aware it can overwhelm production systems.

Only run benchmark tests against servers you own or have explicit permission to test. Aggressive load testing against third-party servers may violate terms of service and could be interpreted as a denial-of-service attack.

Test Multiple URLs

In practice, real-world traffic hits multiple pages. First, create a file containing URLs to test:

nano ~/urls.txt

Then, add your target URLs, one per line:

https://example.com/
https://example.com/about
https://example.com/contact
https://example.com/products

Next, run Siege with the -f flag to read URLs from the file:

siege -c 25 -t 2M -f ~/urls.txt

During testing, Siege randomly selects URLs from the file, simulating realistic user navigation patterns.

Internet Simulation Mode

The -i flag enables internet simulation, which randomly selects URLs and adds variable delays to mimic real user behavior:

siege -c 25 -t 5M -i -f ~/urls.txt

As a result, this mode provides more realistic load patterns compared to pure benchmark testing.

Add Custom Headers

Test authenticated endpoints or API requests by adding custom headers with -H:

siege -c 10 -t 30S -H "Authorization: Bearer your-token-here" https://api.example.com/endpoint

Additionally, you can specify multiple headers by using -H multiple times:

siege -c 10 -t 30S \
  -H "Authorization: Bearer your-token-here" \
  -H "Content-Type: application/json" \
  https://api.example.com/endpoint

JSON Output for Automation

If you need scripting and monitoring integration, you can use --json-output to get machine-readable results:

siege -c 25 -t 30S --json-output -q https://example.com

In this case, the -q (quiet) flag suppresses per-request output, leaving only the final JSON statistics:

{"transactions": 850, "availability": 100.00, "elapsed_time": 30.05, "data_transferred": 0.98, "response_time": 0.18, "transaction_rate": 28.29, "throughput": 0.03, "concurrency": 5.02, "successful_transactions": 850, "failed_transactions": 0, "longest_transaction": 0.92, "shortest_transaction": 0.07}

Enable Logging

To save test results for historical analysis, use the --log flag:

siege --log=~/siege-results.log -c 50 -t 1M https://example.com

Each test appends a summary line to the log file, allowing you to track performance changes over time.

Realistic Delay Between Requests

Real users don’t click continuously. The -d flag adds a random delay (up to the specified seconds) between each simulated user’s requests:

siege -c 50 -t 5M -d 3 https://example.com

As a result, this introduces 0-3 seconds of delay between requests, better simulating how actual visitors interact with your site.

Interpret Siege Results

Understanding Siege’s output is essential for identifying bottlenecks and measuring improvements. Here is what each metric means:

Transactions

Total number of completed HTTP requests
Higher is generally better, but context matters

Availability

Percentage of successful requests
Should be 100% under normal conditions; values below 99% indicate problems

Response time

Average time to complete each request
Lower is better; under 0.5 seconds is generally acceptable for web pages

Transaction rate

Requests completed per second
Your server’s throughput capacity

Concurrency

Average number of simultaneous connections during the test
Should be close to your -c value; significantly lower indicates connection bottlenecks

Failed transactions

Requests that received errors or timeouts
Any value above 0 warrants investigation

Update Siege

Update APT-Installed Siege

If you installed Siege via APT, updates arrive through normal system upgrades:

sudo apt update
sudo apt install --only-upgrade siege

This command uses the --only-upgrade flag, which updates Siege only if a newer version is available, without installing it fresh if previously removed.

Update Source-Compiled Siege

For source installations, you can either run the commands manually or use an automated script. Here are both options:

Option 1: Manual Update

To update manually, download the latest source and recompile:

cd ~
wget https://download.joedog.org/siege/siege-latest.tar.gz
tar -xzf siege-latest.tar.gz
cd siege-*/
./configure
make
sudo make install

Option 2: Automated Update Script

Alternatively, create a reusable update script that checks versions, downloads, compiles, and cleans up automatically. First, create the script file:

nano ~/update-siege.sh

Then, paste the following content:

#!/bin/bash
# Siege Source Update Script
# Downloads, compiles, and installs the latest Siege version
# Usage: ./update-siege.sh [--local]
#   --local: Install to ~/.local (no sudo required)

set -e

# Parse arguments
LOCAL_INSTALL=false
if [ "$1" = "--local" ]; then
    LOCAL_INSTALL=true
fi

BUILD_DIR="${HOME}/siege-build"
DOWNLOAD_URL="https://download.joedog.org/siege/siege-latest.tar.gz"

echo "=== Siege Source Update Script ==="

if [ "$LOCAL_INSTALL" = true ]; then
    echo "Mode: User-local installation (no sudo required)"
    INSTALL_PREFIX="$HOME/.local"
else
    echo "Mode: System-wide installation (requires sudo)"
    INSTALL_PREFIX="/usr/local"
fi

# Check for required tools
echo -e "\nChecking prerequisites..."
for cmd in wget tar make gcc; do
    if ! command -v "$cmd" &> /dev/null; then
        echo "Error: $cmd is not installed."
        echo "Install dependencies: sudo apt install build-essential libssl-dev zlib1g-dev wget"
        exit 1
    fi
done
echo "All prerequisites found."

# Check current version
if command -v siege &> /dev/null; then
    CURRENT_VERSION=$(siege --version 2>&1 | head -1 | awk '{print $2}')
    echo "Current Siege version: ${CURRENT_VERSION}"
else
    echo "Siege is not currently installed."
    CURRENT_VERSION="none"
fi

# Create build directory and download
echo -e "\nCreating build directory..."
mkdir -p "$BUILD_DIR"
cd "$BUILD_DIR"

echo -e "\nDownloading latest Siege source..."
rm -f siege-latest.tar.gz
wget -q --show-progress "$DOWNLOAD_URL"

echo -e "\nExtracting archive..."
rm -rf siege-*/
tar -xzf siege-latest.tar.gz

# Check version and compile
cd siege-*/
NEW_VERSION=$(grep "PACKAGE_VERSION=" configure | cut -d'=' -f2 | tr -d "'")
echo "Latest available version: ${NEW_VERSION}"

if [ "$CURRENT_VERSION" = "$NEW_VERSION" ]; then
    echo -e "\nSiege is already up to date (version ${NEW_VERSION})."
    exit 0
fi

echo -e "\nConfiguring build..."
./configure --prefix="$INSTALL_PREFIX" --quiet

echo -e "\nCompiling..."
make -j$(nproc) --quiet

echo -e "\nInstalling..."
if [ "$LOCAL_INSTALL" = true ]; then
    make install --quiet
else
    sudo make install --quiet
fi

# Verify and cleanup
echo -e "\nVerifying installation..."
INSTALLED_VERSION=$(siege --version 2>&1 | head -1 | awk '{print $2}')
echo "Successfully installed Siege ${INSTALLED_VERSION}"

echo -e "\nCleaning up..."
cd "$HOME"
rm -rf "$BUILD_DIR"

echo -e "\n=== Update complete ==="

After saving the file, make it executable:

chmod +x ~/update-siege.sh

Now you can run the script with or without the --local flag:

# System-wide update (requires sudo)
~/update-siege.sh

# User-local update (no sudo required)
~/update-siege.sh --local

Expected output when updating from version 4.1.6 to 4.1.7:

=== Siege Source Update Script ===

Checking prerequisites...
All prerequisites found.
Current Siege version: 4.1.6

Creating build directory...

Downloading latest Siege source...
siege-latest.tar.gz  100%[==================>] 530.71K  2.50MB/s    in 0.2s

Extracting archive...
Latest available version: 4.1.7

Configuring build...

Compiling...

Installing (requires sudo)...

Verifying installation...
Successfully installed Siege 4.1.7

Cleaning up...

=== Update complete ===

Do not run this script via cron or automated schedulers. Source compilation should always be performed interactively so you can address any dependency issues or compilation errors that may arise.

Fortunately, your configuration file remains intact during updates since it resides in your home directory.

Troubleshoot Common Issues

Connection Refused or Timeout Errors

If Siege reports connection failures, verify the target server is accessible:

curl -I https://example.com

If curl works but Siege fails, the target server may be rate-limiting or blocking load testing tools based on the User-Agent string. In that case, try using a custom user agent:

siege -A "Mozilla/5.0 (Windows NT 10.0; Win64; x64)" https://example.com

Too Many Open Files

High concurrency tests may hit your system’s file descriptor limit:

[error] socket: unable to connect sock.c:282: Too many open files

First, check your current limit:

ulimit -n

Then, temporarily increase the limit for your session:

ulimit -n 65535

For permanent changes, edit /etc/security/limits.conf and add lines for your user.

SSL Certificate Errors

Self-signed or expired certificates cause SSL handshake failures. Siege validates certificates by default. If you encounter SSL errors, first verify the target URL works in curl:

curl -v https://example.com 2>&1 | grep -i ssl

For testing environments with self-signed certificates, either ensure your system trusts the certificate or use HTTP for local testing instead. Note that the APT-installed Siege version (4.0.7) on Debian 11/12 has more limited SSL options than newer source-compiled versions.

Production load tests should always use valid certificates to accurately simulate real user connections. Testing against self-signed certificates gives inaccurate results since SSL handshake overhead differs from production environments.

Low Concurrency Despite High User Count

If reported concurrency is much lower than your -c value, the server is responding faster than Siege can generate requests. This is actually a positive result, indicating your server handles load efficiently. To generate more load, increase the concurrent user count or use benchmark mode (-b).

Remove Siege

Remove APT-Installed Siege

To uninstall the APT-installed version, run the following commands:

sudo apt remove --purge siege
sudo apt autoremove

The autoremove command then cleans up any orphaned dependencies that were installed alongside Siege.

Remove Source-Compiled Siege

If you compiled Siege from source, delete the installed binaries and man pages manually:

sudo rm /usr/local/bin/siege
sudo rm /usr/local/bin/bombardment
sudo rm /usr/local/bin/siege2csv.pl
sudo rm /usr/local/bin/siege.config
sudo rm /usr/local/etc/siegerc
sudo rm /usr/local/etc/urls.txt
sudo rm -rf /usr/local/share/man/man1/siege*

Remove User Configuration

The following command permanently deletes your Siege configuration and any custom URL files in the .siege directory. If you have customizations you want to preserve, back them up first.

To delete the user configuration directory:

rm -rf ~/.siege

Clean Up Source Files

Finally, delete the downloaded source archive and extracted directory:

rm -rf ~/siege-latest.tar.gz ~/siege-*/

Verify Removal

To confirm that Siege is no longer installed:

which siege

If removal succeeded, this command produces no output. Conversely, any path displayed indicates files remain.

Conclusion

You now have Siege installed and configured for HTTP load testing on Debian. Throughout this guide, the examples covered range from basic availability checks to realistic multi-URL simulations with custom headers. By using these techniques, you can validate server capacity, identify bottlenecks, and measure the impact of performance optimizations before deploying to production.