diff --git a/src/metrics.js b/src/metrics.js
index 362e99515..99286ede9 100644
--- a/src/metrics.js
+++ b/src/metrics.js
@@ -14,6 +14,7 @@ const apps = require('./apps.js'),
     docker = require('./docker.js'),
     fs = require('node:fs'),
     net = require('node:net'),
+    network = require('./network.js'),
     os = require('node:os'),
     { Readable } = require('node:stream'),
     safe = require('safetydance'),
@@ -141,18 +142,7 @@ async function readDiskMetrics() {
 }
 
 async function readNetworkMetrics() {
-    const contents = await fs.promises.readFile('/proc/net/route', { encoding: 'utf8' });
-    const lines = contents.trim().split('\n').slice(1); // skip header
-
-    let defaultIface = null;
-    for (const line of lines) {
-        const [iface, destination] = line.split(/\s+/);
-        if (destination === '00000000') {
-            defaultIface = iface; // default route
-            break;
-        }
-    }
-    if (!defaultIface) throw new BoxError(BoxError.EXTERNAL_ERROR, 'Could not detect default interface');
+    const defaultIface = await network.getDefaultInterface();
 
     const [rx, tx] = await Promise.all([
         fs.promises.readFile(`/sys/class/net/${defaultIface}/statistics/rx_bytes`, { encoding: 'utf8' }),
diff --git a/src/network.js b/src/network.js
index a55a6bb95..5b246dbee 100644
--- a/src/network.js
+++ b/src/network.js
@@ -19,7 +19,9 @@ exports = module.exports = {
     getIPv4,
     hasIPv6,
     getIPv6,
-    detectIP
+    detectIP,
+
+    getDefaultInterface
 };
 
 const assert = require('node:assert'),
@@ -36,6 +38,8 @@ const assert = require('node:assert'),
 
 const SET_BLOCKLIST_CMD = path.join(__dirname, 'scripts/setblocklist.sh');
 
+let gDefaultIface = null; // cache
+
 function api(provider) {
     assert.strictEqual(typeof provider, 'string');
 
@@ -171,3 +175,31 @@ async function detectIP() {
         ipv6: error6 ? null : ipv6
     };
 }
+
+async function getDefaultInterface() {
+    if (gDefaultIface) return gDefaultIface;
+
+    const contents4 = await fs.promises.readFile('/proc/net/route', { encoding: 'utf8' });
+    const lines4 = contents4.trim().split('\n').slice(1); // skip header
+
+    for (const line of lines4) {
+        const cols = line.trim().split(/\s+/); // Iface, dest, gw, flags, refcount, use, metric, mask, mtu, window, irtt
+        if (cols[1] === '00000000') { // && cols[7] === '00000000'
+            gDefaultIface = cols[0];
+            return gDefaultIface;
+        }
+    }
+
+    const contents6 = await fs.promises.readFile('/proc/net/ipv6_route', { encoding: 'utf8' });
+    const lines6 = contents6.trim().split('\n'); // no header!
+
+    for (const line of lines6) {
+        const cols = line.trim().split(/\s+/); // dest, dest_prefix_len, src, src_prefix_len, next_hop, metric, refcount, use, flags, iface
+        if (cols[0] === '00000000000000000000000000000000' && cols[1] === '00') {
+            gDefaultIface = cols.at(-1);
+            return gDefaultIface;
+        }
+    }
+
+    throw new BoxError(BoxError.EXTERNAL_ERROR, 'Could not detect default interface');
+}
diff --git a/src/test/network-test.js b/src/test/network-test.js
index f6b0c73a0..bda2628ca 100644
--- a/src/test/network-test.js
+++ b/src/test/network-test.js
@@ -141,4 +141,10 @@ describe('Network', function () {
             expect(await network.getDynamicDns()).to.be(true);
         });
     });
+
+    describe('Default interface', function () {
+        it('can get default interface', async function () {
+            expect(await network.getDefaultInterface()).to.be.ok();
+        });
+    });
 });