diff --git a/go.mod b/go.mod
index b184690..827d4bf 100644
--- a/go.mod
+++ b/go.mod
@@ -8,9 +8,10 @@ require (
 	github.com/google/go-cmp v0.4.0 // indirect
 	github.com/google/gopacket v1.1.16
 	github.com/mdlayher/raw v0.0.0-20190303161257-764d452d77af
+	github.com/mdlayher/watchdog v0.0.0-20201005150459-8bdc4f41966b
 	github.com/rtr7/dhcp4 v0.0.0-20181120124042-778e8c2e24a5
 	github.com/stretchr/testify v1.5.1 // indirect
-	golang.org/x/crypto v0.0.0-20191206172530-e9b2fee46413
-	golang.org/x/sys v0.0.0-20200406155108-e3b113bbe6a4
+	golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 // indirect
+	golang.org/x/sys v0.0.0-20201005065044-765f4ea38db3
 	rsc.io/goversion v1.2.0
 )
diff --git a/go.sum b/go.sum
index 06b56fe..7ea0c2f 100644
--- a/go.sum
+++ b/go.sum
@@ -2,11 +2,6 @@ github.com/beevik/ntp v0.2.0 h1:sGsd+kAXzT0bfVfzJfce04g+dSRfrs+tbQW8lweuYgw=
 github.com/beevik/ntp v0.2.0/go.mod h1:hIHWr+l3+/clUnF44zdK+CWW7fO8dR5cIylAQ76NRpg=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/gokrazy/internal v0.0.0-20200407065509-37efc446ad44/go.mod h1:LA5TQy7LcvYGQOy75tkrYkFUhbV2nl5qEBP47PSi2JA=
-github.com/gokrazy/internal v0.0.0-20200407075822-660ad467b7c9 h1:x5jR/nNo4/kMSoNo/nwa2xbL7PN1an8S3oIn4OZJdec=
-github.com/gokrazy/internal v0.0.0-20200407075822-660ad467b7c9/go.mod h1:LA5TQy7LcvYGQOy75tkrYkFUhbV2nl5qEBP47PSi2JA=
-github.com/gokrazy/internal v0.0.0-20200530170418-389acc6d0821 h1:H8TFA9ZURF3PrJAhMCvG9uUDrxhrHtULYz4V6qPJcnc=
-github.com/gokrazy/internal v0.0.0-20200530170418-389acc6d0821/go.mod h1:LA5TQy7LcvYGQOy75tkrYkFUhbV2nl5qEBP47PSi2JA=
 github.com/gokrazy/internal v0.0.0-20200531194636-d96421c60091 h1:gP2Z4WgsQl35mlNf4kqYW0D8KnYMC4kdsczagvVKBbg=
 github.com/gokrazy/internal v0.0.0-20200531194636-d96421c60091/go.mod h1:LA5TQy7LcvYGQOy75tkrYkFUhbV2nl5qEBP47PSi2JA=
 github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
@@ -15,6 +10,8 @@ github.com/google/gopacket v1.1.16 h1:u6Afvia5C5srlLcbTwpHaFW918asLYPxieziOaWwz8
 github.com/google/gopacket v1.1.16/go.mod h1:UCLx9mCmAwsVbn6qQl1WIEt2SO7Nd2fD0th1TBAsqBw=
 github.com/mdlayher/raw v0.0.0-20190303161257-764d452d77af h1:20h/EjkLGn9mV5nX9MFnGhbbeEhIGnOKPShJfBtVkVQ=
 github.com/mdlayher/raw v0.0.0-20190303161257-764d452d77af/go.mod h1:rC/yE65s/DoHB6BzVOUBNYBGTg772JVytyAytffIZkY=
+github.com/mdlayher/watchdog v0.0.0-20201005150459-8bdc4f41966b h1:7tUBfsEEBWfFeHOB7CUfoOamak+Gx/BlirfXyPk1WjI=
+github.com/mdlayher/watchdog v0.0.0-20201005150459-8bdc4f41966b/go.mod h1:bmoJUS6qOA3uKFvF3KVuhf7mU1KQirzQMeHXtPyKEqg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rtr7/dhcp4 v0.0.0-20181120124042-778e8c2e24a5 h1:/kzTBQ20DbbhSNaBXiFEk2gPrGhY26kajwC1ro/Vlh8=
@@ -23,15 +20,13 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20191206172530-e9b2fee46413 h1:ULYEB3JvPRE/IfO+9uO7vKV/xzVTO7XPAwm8xbf4w2g=
-golang.org/x/crypto v0.0.0-20191206172530-e9b2fee46413/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200406155108-e3b113bbe6a4 h1:c1Sgqkh8v6ZxafNGG64r8C8UisIW2TKMJN8P86tKjr0=
 golang.org/x/sys v0.0.0-20200406155108-e3b113bbe6a4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201005065044-765f4ea38db3 h1:9Dt0vhJUQR70NuYBi/EFF+uAOebN40T4F1PZ7PKYrdw=
+golang.org/x/sys v0.0.0-20201005065044-765f4ea38db3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
diff --git a/gokrazy.go b/gokrazy.go
index ce6f5ec..24b3357 100644
--- a/gokrazy.go
+++ b/gokrazy.go
@@ -20,6 +20,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/mdlayher/watchdog"
 	"golang.org/x/sys/unix"
 
 	"github.com/gokrazy/gokrazy/internal/iface"
@@ -51,17 +52,28 @@ func configureLoopback() error {
 	return cs.SetNetmask(net.IPMask([]byte{255, 0, 0, 0}))
 }
 
-// watchdog periodically pings the hardware watchdog.
-func watchdog() {
-	f, err := os.OpenFile("/dev/watchdog", os.O_WRONLY, 0)
+// runWatchdog periodically pings the hardware watchdog.
+func runWatchdog() {
+	d, err := watchdog.Open()
 	if err != nil {
 		log.Printf("disabling hardware watchdog, as it could not be opened: %v", err)
 		return
 	}
-	defer f.Close()
+	defer d.Close()
+
+	var timeout string
+	if t, err := d.Timeout(); err != nil {
+		// Assume the device cannot report the watchdog timeout.
+		timeout = "unknown"
+	} else {
+		timeout = t.String()
+	}
+
+	log.Printf("found hardware watchdog %q with timeout %s, pinging...", d.Identity, timeout)
+
 	for {
-		if _, _, errno := unix.Syscall(unix.SYS_IOCTL, f.Fd(), unix.WDIOC_KEEPALIVE, 0); errno != 0 {
-			log.Printf("hardware watchdog ping failed: %v", errno)
+		if err := d.Ping(); err != nil {
+			log.Printf("hardware watchdog ping failed: %v", err)
 		}
 		time.Sleep(1 * time.Second)
 	}
@@ -107,7 +119,7 @@ func setupTLS() error {
 // userBuildTimestamp will be exposed on the HTTP status handlers that
 // are set up by Supervise.
 func Boot(userBuildTimestamp string) error {
-	go watchdog()
+	go runWatchdog()
 
 	buildTimestamp = userBuildTimestamp