diff --git a/app/src/main/java/eu/faircode/email/ActivityDmarc.java b/app/src/main/java/eu/faircode/email/ActivityDmarc.java
index d8acef4b59..f6981b5480 100644
--- a/app/src/main/java/eu/faircode/email/ActivityDmarc.java
+++ b/app/src/main/java/eu/faircode/email/ActivityDmarc.java
@@ -282,7 +282,7 @@ public class ActivityDmarc extends ActivityBase {
                                                                 Integer prefix = Helper.parseInt(net[1]);
                                                                 if (prefix == null)
                                                                     continue;
-                                                                if (inSubnet(text, net[0], prefix)) {
+                                                                if (ConnectionHelper.inSubnet(text, net[0], prefix)) {
                                                                     valid = true;
                                                                     break;
                                                                 }
@@ -504,31 +504,6 @@ public class ActivityDmarc extends ActivityBase {
                 }
                 return result;
             }
-
-            private boolean inSubnet(final String ip, final String net, final int prefix) {
-                try {
-                    byte[] _ip = InetAddress.getByName(ip).getAddress();
-                    byte[] _net = InetAddress.getByName(net).getAddress();
-
-                    if (_ip.length != _net.length)
-                        return false;
-
-                    int i = 0;
-                    int p = prefix;
-                    while (p >= 8) {
-                        if (_ip[i] != _net[i])
-                            return false;
-                        ++i;
-                        p -= 8;
-                    }
-
-                    int m = (0xFF00 >> p) & 0xFF;
-                    return (_ip[i] & m) == (_net[i] & m);
-                } catch (Throwable ex) {
-                    Log.w(ex);
-                    return false;
-                }
-            }
         }.execute(this, args, "dmarc:decode");
     }
 }
diff --git a/app/src/main/java/eu/faircode/email/ConnectionHelper.java b/app/src/main/java/eu/faircode/email/ConnectionHelper.java
index 2c15b1a7fb..ad78278e1c 100644
--- a/app/src/main/java/eu/faircode/email/ConnectionHelper.java
+++ b/app/src/main/java/eu/faircode/email/ConnectionHelper.java
@@ -518,6 +518,31 @@ public class ConnectionHelper {
         }
     }
 
+    static boolean inSubnet(final String ip, final String net, final int prefix) {
+        try {
+            byte[] _ip = InetAddress.getByName(ip).getAddress();
+            byte[] _net = InetAddress.getByName(net).getAddress();
+
+            if (_ip.length != _net.length)
+                return false;
+
+            int i = 0;
+            int p = prefix;
+            while (p >= 8) {
+                if (_ip[i] != _net[i])
+                    return false;
+                ++i;
+                p -= 8;
+            }
+
+            int m = (0xFF00 >> p) & 0xFF;
+            return (_ip[i] & m) == (_net[i] & m);
+        } catch (Throwable ex) {
+            Log.w(ex);
+            return false;
+        }
+    }
+
     static List<String> getCommonNames(Context context, String domain, int port, int timeout) throws IOException {
         List<String> result = new ArrayList<>();
         InetSocketAddress address = new InetSocketAddress(domain, port);