diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index 1e6d7a1975..996c8245ba 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -53,6 +53,7 @@ import javax.mail.MessagingException;
 import javax.mail.Multipart;
 import javax.mail.Part;
 import javax.mail.Session;
+import javax.mail.internet.AddressException;
 import javax.mail.internet.ContentType;
 import javax.mail.internet.InternetAddress;
 import javax.mail.internet.MimeBodyPart;
@@ -456,6 +457,24 @@ public class MessageHelper {
         return (TextUtils.isEmpty(msgid) ? Long.toString(uid) : msgid);
     }
 
+    Address getSender() throws MessagingException {
+        String sender = imessage.getHeader("Sender", null);
+        if (sender == null)
+            return null;
+
+        InternetAddress[] address = null;
+        try {
+            address = InternetAddress.parse(sender);
+        } catch (AddressException ex) {
+            Log.w(ex);
+        }
+
+        if (address == null || address.length == 0)
+            return null;
+
+        return address[0];
+    }
+
     Address[] getFrom() throws MessagingException {
         return imessage.getFrom();
     }
@@ -560,7 +579,7 @@ public class MessageHelper {
         private Part plain = null;
         private Part html = null;
         private List<AttachmentPart> attachments = new ArrayList<>();
-        private List<String> warnings = new ArrayList<>();
+        private ArrayList<String> warnings = new ArrayList<>();
 
         String getHtml(Context context) throws MessagingException {
             if (plain == null && html == null) {
@@ -709,7 +728,9 @@ public class MessageHelper {
             }
         }
 
-        String getWarnings() {
+        String getWarnings(String existing) {
+            if (existing != null)
+                warnings.add(0, existing);
             if (warnings.size() == 0)
                 return null;
             else
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index 5d9e62f86d..419c7817c9 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -1969,7 +1969,7 @@ public class ServiceSynchronize extends LifecycleService {
         String preview = HtmlHelper.getPreview(body);
         message.write(this, body);
         db.message().setMessageContent(message.id, true, preview);
-        db.message().setMessageWarning(message.id, parts.getWarnings());
+        db.message().setMessageWarning(message.id, parts.getWarnings(message.warning));
     }
 
     private void doAttachment(EntityFolder folder, EntityOperation op, IMAPFolder ifolder, EntityMessage message, JSONArray jargs, DB db) throws JSONException, MessagingException, IOException {
@@ -2515,6 +2515,17 @@ public class ServiceSynchronize extends LifecycleService {
             message.ui_ignored = seen;
             message.ui_browsed = browsed;
 
+            // Check sender
+            Address sender = helper.getSender();
+            if (sender != null && senders.length > 0) {
+                String[] f = ((InternetAddress) senders[0]).getAddress().split("@");
+                String[] s = ((InternetAddress) sender).getAddress().split("@");
+                if (f.length > 1 && s.length > 1) {
+                    if (!f[1].equals(s[1]))
+                        message.warning = context.getString(R.string.title_via, s[1]);
+                }
+            }
+
             message.id = db.message().insertMessage(message);
 
             Log.i(folder.name + " added id=" + message.id + " uid=" + message.uid);
@@ -2658,7 +2669,7 @@ public class ServiceSynchronize extends LifecycleService {
                 String body = parts.getHtml(context);
                 message.write(context, body);
                 db.message().setMessageContent(message.id, true, HtmlHelper.getPreview(body));
-                db.message().setMessageWarning(message.id, parts.getWarnings());
+                db.message().setMessageWarning(message.id, parts.getWarnings(message.warning));
                 Log.i(folder.name + " downloaded message id=" + message.id + " size=" + message.size);
             }
         }
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 8fb62aae66..e4a0751e4a 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -459,6 +459,7 @@
     <string name="title_no_adobe">Adobe Acrobat reader cannot open safely shared files, see the FAQ for more information</string>
     <string name="title_no_body">No message text found</string>
     <string name="title_no_charset">Unsupported encoding: %1$s</string>
+    <string name="title_via">Via: %1$s</string>
 
     <string name="title_try">Try FairEmail, an open source, privacy friendly email app for Android</string>