diff --git a/src/shadowbox/docker/Dockerfile b/src/shadowbox/docker/Dockerfile
index e62ec115..0ad8cb1e 100644
--- a/src/shadowbox/docker/Dockerfile
+++ b/src/shadowbox/docker/Dockerfile
@@ -25,8 +25,8 @@ LABEL shadowbox.outline-ss-server_version="${SS_VERSION}"
 ARG GITHUB_RELEASE
 LABEL shadowbox.github.release="${GITHUB_RELEASE}"
 
-# lsof for Shadowbox, curl for detecting our public IP.
-RUN apk add --no-cache lsof curl
+# We use curl to detect the server's public IP.
+RUN apk add --no-cache curl
 
 COPY src/shadowbox/scripts scripts/
 COPY src/shadowbox/scripts/update_mmdb.sh /etc/periodic/weekly/update_mmdb
diff --git a/src/shadowbox/infrastructure/get_port.spec.ts b/src/shadowbox/infrastructure/get_port.spec.ts
index eb9d35f2..1539f7d7 100644
--- a/src/shadowbox/infrastructure/get_port.spec.ts
+++ b/src/shadowbox/infrastructure/get_port.spec.ts
@@ -60,19 +60,3 @@ function listen(): Promise<net.Server> {
     });
   });
 }
-
-describe('getUsedPorts', () => {
-  it('returns used port', async () => {
-    const server = await listen();
-    const serverPort = server.address().port;
-    const usedPorts = await get_port.getUsedPorts();
-    expect(usedPorts).toContain(serverPort);
-
-    const onceClosed = new Promise((resolve, reject) => {
-      server.on('close', () => resolve());
-    });
-    server.close();
-    await onceClosed;
-    expect(await get_port.getUsedPorts()).not.toContain(serverPort);
-  });
-});
\ No newline at end of file
diff --git a/src/shadowbox/infrastructure/get_port.ts b/src/shadowbox/infrastructure/get_port.ts
index bd25fa8c..cf39d840 100644
--- a/src/shadowbox/infrastructure/get_port.ts
+++ b/src/shadowbox/infrastructure/get_port.ts
@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import * as child_process from 'child_process';
 import * as net from 'net';
 
 const MAX_PORT = 65535;
@@ -66,36 +65,6 @@ function getRandomPortOver1023() {
   return Math.floor(Math.random() * (MAX_PORT + 1 - MIN_PORT) + MIN_PORT);
 }
 
-// Returns the list of ports used by either TCP or UDP.
-export function getUsedPorts(): Promise<Set<number>> {
-  return new Promise((resolve, reject) => {
-    child_process.exec('lsof -P -i -F n', (error, stdout, stderr) => {
-      const tcpPorts = new Set<number>();
-      if (error) {
-        if (error.code === 1) {
-          // Empty list case
-          return resolve(tcpPorts);
-        }
-        return reject(error);
-      }
-      for (const line of stdout.split(/\r?\n/)) {
-        if (line.length === 0 || line[0] !== 'n') {
-          continue;
-        }
-        const parts = line.split(':');
-        if (parts.length !== 2) {
-          continue;
-        }
-        const port = parseInt(parts[1], 10);
-        if (port) {
-          tcpPorts.add(port);
-        }
-      }
-      resolve(tcpPorts);
-    });
-  });
-}
-
 interface ServerError extends Error {
   code: string;
 }