--- dovecot-2.2.33.2/src/lib-mail/mail-user-hash.c	2017-10-05 18:10:44.000000000 +0100
+++ dovecot-2.2.33.2.reverse-domaincut/src/lib-mail/mail-user-hash.c	2017-11-02 16:04:03.724866755 +0000
@@ -33,9 +33,13 @@
 		tab = t_malloc(sizeof(static_tab));
 		memcpy(tab, static_tab, sizeof(static_tab));
 		tab[0].value = username;
-		tab[1].value = t_strcut(username, '@');
-		tab[2].value = strchr(username, '@');
-		if (tab[2].value != NULL) tab[2].value++;
+		tab[2].value = strrchr(username, '@');
+		if (tab[2].value != NULL) {
+			tab[1].value = t_strdup_until(username, tab[2].value);
+			tab[2].value++;
+		} else {
+			tab[1].value = username;
+		}
 
 		var_expand(str, format, tab);
 		md5_get_digest(str_data(str), str_len(str), md5);
--- dovecot-2.2.33.2/src/lib-mail/message-address.c	2017-10-05 18:10:44.000000000 +0100
+++ dovecot-2.2.33.2.reverse-domaincut/src/lib-mail/message-address.c	2017-11-02 16:00:30.926866755 +0000
@@ -540,7 +540,7 @@
 	if (*delimiter_string == '\0')
 		return;
 
-	domain = strchr(address, '@');
+	domain = strrchr(address, '@');
 	p = strstr(address, delimiter_string);
 	if (p != NULL && (domain == NULL || p < domain)) {
 		/* user+detail@domain */