diff --git a/degesch.c b/degesch.c
index f997471..a1920cb 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1059,6 +1059,8 @@ struct server
 	// TODO: an output queue to prevent excess floods (this will be needed
 	//   especially for away status polling)
 
+	bool rehashing;                     ///< Rehashing IRC identifiers
+
 	struct str_map irc_users;           ///< IRC user data
 	struct str_map irc_channels;        ///< IRC channel data
 	struct str_map irc_buffer_map;      ///< Maps IRC identifiers to buffers
@@ -2791,7 +2793,8 @@ irc_user_on_destroy (void *object, void *user_data)
 {
 	struct user *user = object;
 	struct server *s = user_data;
-	str_map_set (&s->irc_users, user->nickname, NULL);
+	if (!s->rehashing)
+		str_map_set (&s->irc_users, user->nickname, NULL);
 }
 
 static struct user *
@@ -2877,7 +2880,8 @@ irc_channel_on_destroy (void *object, void *user_data)
 	struct server *s = user_data;
 	LIST_FOR_EACH (struct channel_user, iter, channel->users)
 		irc_channel_unlink_user (channel, iter);
-	str_map_set (&s->irc_channels, channel->name, NULL);
+	if (!s->rehashing)
+		str_map_set (&s->irc_channels, channel->name, NULL);
 }
 
 static struct channel *
@@ -2924,7 +2928,74 @@ irc_left_channel (struct channel *channel)
 static void
 irc_rehash_and_fix_conflicts (struct server *s)
 {
-	// TODO
+	// Save the old maps and initialize new ones
+	struct str_map old_users      = s->irc_users;
+	struct str_map old_channels   = s->irc_channels;
+	struct str_map old_buffer_map = s->irc_buffer_map;
+
+	str_map_init (&s->irc_users);
+	str_map_init (&s->irc_channels);
+	str_map_init (&s->irc_buffer_map);
+
+	s->irc_users     .free = old_users     .free;
+	s->irc_channels  .free = old_channels  .free;
+	s->irc_buffer_map.free = old_buffer_map.free;
+
+	s->irc_users     .key_xfrm = s->irc_strxfrm;
+	s->irc_channels  .key_xfrm = s->irc_strxfrm;
+	s->irc_buffer_map.key_xfrm = s->irc_strxfrm;
+
+	// Prevent channels and users from unsetting themselves
+	// from server maps upon removing the last reference to them
+	s->rehashing = true;
+
+	// TODO: "Removed similarly named buffer %s because of casemapping conflict"
+	// XXX: to be perfectly sure, we should also check
+	//   whether any users collide with channels and vice versa
+
+	struct str_map_iter iter;
+	str_map_iter_init (&iter, &old_users);
+	struct user *user;
+	while ((user = str_map_iter_next (&iter)))
+	{
+		// FIXME: don't remove ourselves!
+		if (str_map_find (&s->irc_users, user->nickname))
+		{
+			// TODO: move or merge any PM buffer and remove
+			//   the user from channels and altogether
+		}
+		else
+		{
+			str_map_set (&s->irc_users, user->nickname, user);
+			str_map_set (&s->irc_buffer_map, user->nickname,
+				str_map_find (&old_buffer_map, user->nickname));
+		}
+	}
+
+	str_map_iter_init (&iter, &old_channels);
+	struct channel *channel;
+	while ((channel = str_map_iter_next (&iter)))
+	{
+		if (str_map_find (&s->irc_channels, channel->name))
+		{
+			// TODO: remove all users from the buffer
+			//   and probably issue NAMES if registered and on the channel,
+			//   and of course remove the colliding channel
+		}
+		else
+		{
+			str_map_set (&s->irc_channels, channel->name, user);
+			str_map_set (&s->irc_buffer_map, user->nickname,
+				str_map_find (&old_buffer_map, user->nickname));
+		}
+	}
+
+	// Hopefully we've either moved or destroyed all the old content
+	s->rehashing = false;
+
+	str_map_free (&old_users);
+	str_map_free (&old_channels);
+	str_map_free (&old_buffer_map);
 }
 
 static void