lsleases captures broadcast ‘DHCP request’ datagrams from any device
(pc, laptop, virtual machine, phone, raspberry, esp32, …) with dynamic ip addresses in your local network.

You can list the captured ip addresses to lookup an assigned ip for a device.

For more information, check the Manual.

1.) install lsleases - see Installation

2.) re-plug / start-up any device with a dynamic ip address

3a.) list captured devices

j@main:~ ⟩ lsleases
Ip               Mac                Host
192.168.1.152    80:d0:9b:xx:xx:xx  android-6298296f6184995a
192.168.1.122    b8:27:eb:xx:xx:xx  raspberrypi
192.168.1.155    5c:cf:7f:xx:xx:xx  NODE-931BFD

3b.) or if you start lsleasesd with the ‘-webui’ option, you can open your browser at http://127.0.0.1:9999 to access the integrated webapp.

You can use lsleases as a go library in your own programs: lsleases go library

I will provide standalone binaries for each platform in the coming days.

! If no leases are captured, make sure your firewall has port 67 (DHCP) open !

sudo iptables -I INPUT -p udp --dport 67 -j ACCEPT

check the Manual for a description.

• Debian / Ubuntu
• Redhat / Fedora
• Windows
• OSX
• FreeBSD
• Build from source (client / server)
• Build from source (standalone)

1.) download the .deb package from http://github.com/j-keck/lsleases/releases/latest

2.) install the package sudo dpkg -i lsleases-<VERSION>-<ARCH>.deb

3.) activate the service sudo systemctl enable lsleasesd

4.) start the daemon sudo systemctl start lsleasesd

1.) download the .rpm package from http://github.com/j-keck/lsleases/releases/latest

2.) install the package sudo rpm -i lsleases-<VERSION>-<ARCH>.rpm

3.) activate the service sudo systemctl enable lsleasesd

4.) start the daemon sudo systemctl start lsleasesd

I provide two packages for windows:

• lsleases-<VERSION>-<ARCH>-windows-installer.exe
• lsleases-<VERSION>-<ARCH>-windows-standalone.zip

check Windows Manual for more information.

1.) download the package from http://github.com/j-keck/lsleases/releases/latest

2.) install per installer or unzip the standalone package

1.) download the lsleases-<VERSION>-<ARCH>-osx-standalone.zip package from http://github.com/j-keck/lsleases/releases/latest

2.) unpack the zip archive and go into the lsleases directory

3.) execute ./capture-leases.sh

1.) download the lsleases-<VERSION>-amd64-freebsd.txz package from http://github.com/j-keck/lsleases/releases/latest

2.) install the package sudo pkg install lsleases-<VERSION>-amd64-freebsd.txz

3.) allow unprivileged users open ports less than 1024 (lsleasesd runs as user nobody)

echo net.inet.ip.portrange.reservedhigh=0 | sudo tee -a /etc/sysctl.conf
sudo service sysctl restart

4.) activate the service sudo sysrc lsleasesd_enable=YES

5.) start the daemon sudo service lsleasesd start

1.) fetch the server

go get -u github.com/j-keck/lsleases/cmd/lsleasesd

2.) start the server

sudo $GOPATH/bin/lsleasesd &

3.) fetch the client

go get -u github.com/j-keck/lsleases/cmd/lsleases

4.) run the client

$GOPATH/bin/lsleases -w

see the Manual for more information.

For a quick test you can use the standalone mode without the server component. In this mode it does not run in the background, has no cache and supports no webui.

1.) fetch the client

go get -u github.com/j-keck/lsleases/cmd/lsleases

2.) run the client in the standalone mode

sudo $GOPATH/bin/lsleases -s

see the Manual for more information.

You can use lsleases as a go library in your own programs. For example to trigger any custom action on device discovery.

package main

import "github.com/j-keck/lsleases/pkg/sniffer"
import "github.com/j-keck/lsleases/pkg/config"
import "github.com/j-keck/plog"

func main() {
  // create a logger instance
  log := plog.GlobalLogger().Add(plog.NewDefaultConsoleLogger())

  // create the sniffer with the default configuration
  cfg := config.NewDefaultConfig()
  sniffer := sniffer.NewSniffer(cfg)

  // subscribe to DHCP leases events and log the events
  go func() {
    leasesC := sniffer.Subscribe(10)
    for {
      lease := <-leasesC
      log.Infof("new lease: %s", lease.String())
    }
  }()

  if err := sniffer.Start(); err == nil {
    log.Info("sniffing ... - hit <CTRL-C> to abort -")
    select {}
  } else {
    panic(err)
  }
}

GO111MODULE=on sudo go run examples/simple-sniffer.go

see Changelog