diff --git a/app/src/main/java/eu/faircode/email/EmailService.java b/app/src/main/java/eu/faircode/email/EmailService.java
index 53f2580999..5194304326 100644
--- a/app/src/main/java/eu/faircode/email/EmailService.java
+++ b/app/src/main/java/eu/faircode/email/EmailService.java
@@ -30,7 +30,10 @@ import org.bouncycastle.asn1.x509.Extension;
 import org.bouncycastle.asn1.x509.GeneralName;
 import org.bouncycastle.asn1.x509.SubjectKeyIdentifier;
 
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
@@ -92,6 +95,7 @@ public class EmailService implements AutoCloseable {
     private boolean harden;
     private boolean useip;
     private String ehlo;
+    private boolean log;
     private boolean debug;
     private Properties properties;
     private Session isession;
@@ -150,6 +154,7 @@ public class EmailService implements AutoCloseable {
         properties = MessageHelper.getSessionProperties();
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+        this.log = prefs.getBoolean("protocol", false);
         this.harden = prefs.getBoolean("ssl_harden", false);
 
         boolean auth_plain = prefs.getBoolean("auth_plain", true);
@@ -515,7 +520,27 @@ public class EmailService implements AutoCloseable {
             String user, String password,
             SSLSocketFactoryService factory) throws MessagingException {
         isession = Session.getInstance(properties, null);
-        isession.setDebug(debug);
+
+        isession.setDebug(debug || log);
+        if (debug || log)
+            isession.setDebugOut(new PrintStream(new OutputStream() {
+                private ByteArrayOutputStream bos = new ByteArrayOutputStream();
+
+                @Override
+                public void write(int b) {
+                    if (((char) b) == '\n') {
+                        String line = bos.toString();
+                        if (!line.endsWith("ignoring socket timeout"))
+                            if (debug)
+                                android.util.Log.i("javamail", user + " " + line);
+                            else
+                                EntityLog.log(context, user + " " + line);
+                        bos.reset();
+                    } else
+                        bos.write(b);
+                }
+            }));
+
         //System.setProperty("mail.socket.debug", Boolean.toString(debug));
         isession.addProvider(new GmailSSLProvider());
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
index a960e6b65f..661572df13 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
@@ -89,6 +89,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private Button btnApp;
     private Button btnMore;
 
+    private SwitchCompat swProtocol;
     private SwitchCompat swDebug;
     private SwitchCompat swAuthPlain;
     private SwitchCompat swAuthLogin;
@@ -106,7 +107,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private final static String[] RESET_OPTIONS = new String[]{
             "shortcuts", "fts", "english", "watchdog", "updates",
             "experiments", "query_threads", "crash_reports", "cleanup_attachments",
-            "debug", "auth_plain", "auth_login", "auth_sasl"
+            "protocol", "debug", "auth_plain", "auth_login", "auth_sasl"
     };
 
     private final static String[] RESET_QUESTIONS = new String[]{
@@ -149,6 +150,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         btnApp = view.findViewById(R.id.btnApp);
         btnMore = view.findViewById(R.id.btnMore);
 
+        swProtocol = view.findViewById(R.id.swProtocol);
         swDebug = view.findViewById(R.id.swDebug);
         swAuthPlain = view.findViewById(R.id.swAuthPlain);
         swAuthLogin = view.findViewById(R.id.swAuthLogin);
@@ -339,6 +341,13 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             }
         });
 
+        swProtocol.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("protocol", checked).apply();
+            }
+        });
+
         swAuthPlain.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -596,6 +605,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         tvUuid.setText(prefs.getString("uuid", null));
         swCleanupAttachments.setChecked(prefs.getBoolean("cleanup_attachments", false));
 
+        swProtocol.setChecked(prefs.getBoolean("protocol", false));
         swDebug.setChecked(prefs.getBoolean("debug", false));
         swAuthPlain.setChecked(prefs.getBoolean("auth_plain", true));
         swAuthLogin.setChecked(prefs.getBoolean("auth_login", true));
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index af154eba97..7fecb7489a 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -130,7 +130,7 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
     private static final List<String> PREF_RELOAD = Collections.unmodifiableList(Arrays.asList(
             "ssl_harden", // force reconnect
             "badge", "unseen_ignored", // force update badge/widget
-            "debug" // force reconnect
+            "protocol", "debug" // force reconnect
     ));
 
     static final int PI_ALARM = 1;
diff --git a/app/src/main/res/layout/fragment_options_misc.xml b/app/src/main/res/layout/fragment_options_misc.xml
index a5e6d0dce4..d35011563f 100644
--- a/app/src/main/res/layout/fragment_options_misc.xml
+++ b/app/src/main/res/layout/fragment_options_misc.xml
@@ -327,6 +327,30 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/btnApp" />
 
+        <androidx.appcompat.widget.SwitchCompat
+            android:id="@+id/swProtocol"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
+            android:text="@string/title_advanced_protocol"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/btnMore"
+            app:switchPadding="12dp" />
+
+        <eu.faircode.email.FixedTextView
+            android:id="@+id/tvProtocolHint"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginEnd="48dp"
+            android:text="@string/title_advanced_protocol_hint"
+            android:textAppearance="@style/TextAppearance.AppCompat.Small"
+            android:textColor="?attr/colorWarning"
+            android:textStyle="italic"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/swProtocol" />
+
         <androidx.appcompat.widget.SwitchCompat
             android:id="@+id/swDebug"
             android:layout_width="0dp"
@@ -335,7 +359,7 @@
             android:text="@string/title_advanced_debug"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/btnMore"
+            app:layout_constraintTop_toBottomOf="@id/tvProtocolHint"
             app:switchPadding="12dp" />
 
         <eu.faircode.email.FixedTextView
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index bbe156d6c4..8306cd5b7b 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -504,6 +504,7 @@
     <string name="title_advanced_experiments">Try experimental features</string>
     <string name="title_advanced_query_threads">Limit parallel database access</string>
     <string name="title_advanced_crash_reports">Send error reports</string>
+    <string name="title_advanced_protocol">Protocol logging</string>
     <string name="title_advanced_debug">Debug mode</string>
     <string name="title_advanced_cleanup_attachments">Delete attachments of old messages</string>
     <string name="title_advanced_cleanup">Cleanup</string>
@@ -585,6 +586,7 @@
     <string name="title_advanced_fts_hint">Enabling this improves search performance, but also increases battery and storage space usage</string>
     <string name="title_advanced_english_hint">This will restart the app</string>
     <string name="title_advanced_experiments_hint">List of current experimental features</string>
+    <string name="title_advanced_protocol_hint">This will significantly increase battery and storage space usage!</string>
     <string name="title_advanced_debug_hint">Enable extra logging and show debug information at various places</string>
     <string name="title_advanced_cleanup_attachments_hint">When manually cleaning, this will remove attachments from messages that are no longer synchronized</string>
     <string name="title_advanced_cleanup_hint">This will delete all temporary files</string>