From e1a701b2647862df2fa40518c9e198fa4a5bf336 Mon Sep 17 00:00:00 2001
From: M66B <M66B@users.noreply.github.com>
Date: Wed, 1 Sep 2021 15:42:21 +0200
Subject: [PATCH] Discovery: check if MX target exists

---
 app/src/main/java/eu/faircode/email/EmailProvider.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/eu/faircode/email/EmailProvider.java b/app/src/main/java/eu/faircode/email/EmailProvider.java
index f1353f2015..d6012456bc 100644
--- a/app/src/main/java/eu/faircode/email/EmailProvider.java
+++ b/app/src/main/java/eu/faircode/email/EmailProvider.java
@@ -308,8 +308,9 @@ public class EmailProvider implements Parcelable {
                 }
 
             for (DnsHelper.DnsRecord record : records)
-                if (!TextUtils.isEmpty(record.name)) {
+                try {
                     String target = record.name.toLowerCase(Locale.ROOT);
+                    InetAddress.getByName(target);
 
                     EmailProvider mx1 = new EmailProvider(domain);
                     mx1.imap.score = 0;
@@ -334,6 +335,8 @@ public class EmailProvider implements Parcelable {
                     candidates.add(mx2);
 
                     break;
+                } catch (UnknownHostException ex) {
+                    Log.w(ex);
                 }
         } catch (Throwable ex) {
             Log.w(ex);