diff --git a/cert/Dockerfile b/cert/Dockerfile
index 84cb44c..df5be10 100644
--- a/cert/Dockerfile
+++ b/cert/Dockerfile
@@ -1,13 +1,12 @@
 # Use ubuntu because it's ez
 FROM ubuntu:latest
 
+WORKDIR /build
+
 # Use openssl and golang to generate certificates
 RUN apt-get update && \
-	apt-get install -y ca-certificates openssl golang
+	apt-get install -y ca-certificates openssl golang xxd
 
-# Save the certificates to a volume
-VOLUME /cert
-WORKDIR /cert
 
 # Download the go modules
 COPY go.mod go.sum ./
@@ -16,5 +15,8 @@ RUN go mod download
 # Copy over the remaining files.
 COPY . .
 
+# Save the certificates to a volume
+VOLUME /cert
+
 # TODO support an output directory
-CMD ./generate
\ No newline at end of file
+CMD ./generate && cp localhost.* /cert
\ No newline at end of file
diff --git a/cert/generate b/cert/generate
index c86b309..63bb335 100755
--- a/cert/generate
+++ b/cert/generate
@@ -17,4 +17,4 @@ go run filippo.io/mkcert -ecdsa -install
 go run filippo.io/mkcert -ecdsa -days 10 -cert-file "$CRT" -key-file "$KEY" localhost 127.0.0.1 ::1
 
 # Compute the sha256 fingerprint of the certificate for WebTransport
-openssl x509 -in "$CRT" -outform der | openssl dgst -sha256 > localhost.hex
\ No newline at end of file
+openssl x509 -in "$CRT" -outform der | openssl dgst -sha256 -binary | xxd -p -c 256 > localhost.hex
\ No newline at end of file
diff --git a/media/Dockerfile b/media/Dockerfile
index f8f36e4..372db90 100644
--- a/media/Dockerfile
+++ b/media/Dockerfile
@@ -1,6 +1,9 @@
 # Create a build image
 FROM ubuntu:latest
 
+# Create the working directory.
+WORKDIR /build
+
 # Install necessary packages
 RUN apt-get update && \
 	apt-get install -y \
@@ -8,13 +11,15 @@ RUN apt-get update && \
 	wget \
 	ffmpeg
 
-# Create a media volume
-VOLUME /media
-WORKDIR /media
-
 # Download a file from the internet, in this case my boy big buck bunny
 RUN wget http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4 -O source.mp4
 
 # Copy an run a script to create a fragmented mp4 (more overhead, easier to split)
 COPY fragment .
-CMD ./fragment
+
+# Create a media volume
+VOLUME /media
+
+# Fragment the media
+# TODO support an output directory
+CMD ./fragment && cp fragmented.mp4 /media
\ No newline at end of file
diff --git a/server/src/main.rs b/server/src/main.rs
index 56441d7..373474c 100644
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -6,7 +6,7 @@ use clap::Parser;
 #[derive(Parser)]
 struct Cli {
     /// Listen on this address
-    #[arg(short, long, default_value = "0.0.0.0:4443")]
+    #[arg(short, long, default_value = "[::]:4443")]
     addr: String,
 
     /// Use the certificate file at this path
diff --git a/web/src/index.ts b/web/src/index.ts
index 2f83061..5c46360 100644
--- a/web/src/index.ts
+++ b/web/src/index.ts
@@ -6,8 +6,8 @@ import fingerprintHex from 'bundle-text:../fingerprint.hex';
 
 // Convert the hex to binary.
 let fingerprint = [];
-for (let c = 0; c < fingerprintHex.length-1; c += 2) {
-    fingerprint.push(parseInt(fingerprintHex.substring(c, c+2), 16));
+for (let c = 0; c < fingerprintHex.length - 1; c += 2) {
+    fingerprint.push(parseInt(fingerprintHex.substring(c, c + 2), 16));
 }
 
 const params = new URLSearchParams(window.location.search)