diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c
index 33925bfbd1..8a0dec1540 100644
--- a/src/shared/dns-domain.c
+++ b/src/shared/dns-domain.c
@@ -529,6 +529,28 @@ int dns_name_endswith(const char *name, const char *suffix) {
         }
 }
 
+int dns_name_between(const char *a, const char *b, const char *c) {
+        int n;
+
+        /* Determine if b is strictly greater than a and strictly smaller than c.
+           We consider the order of names to be circular, so that if a is
+           strictly greater than c, we consider b to be between them if it is
+           either greater than a or smaller than c. This is how the canonical
+           DNS name order used in NSEC records work. */
+
+        n = dns_name_compare_func(a, c);
+        if (n == 0)
+                return -EINVAL;
+        else if (n < 0)
+                /*       a<---b--->c       */
+                return dns_name_compare_func(a, b) < 0 &&
+                       dns_name_compare_func(b, c) < 0;
+        else
+                /* <--b--c         a--b--> */
+                return dns_name_compare_func(b, c) < 0 ||
+                       dns_name_compare_func(a, b) < 0;
+}
+
 int dns_name_reverse(int family, const union in_addr_union *a, char **ret) {
         const uint8_t *p;
         int r;
diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h
index 5728ce34bb..bd50ad3e6d 100644
--- a/src/shared/dns-domain.h
+++ b/src/shared/dns-domain.h
@@ -50,6 +50,7 @@ unsigned long dns_name_hash_func(const void *s, const uint8_t hash_key[HASH_KEY_
 int dns_name_compare_func(const void *a, const void *b);
 extern const struct hash_ops dns_name_hash_ops;
 
+int dns_name_between(const char *a, const char *b, const char *c);
 int dns_name_equal(const char *x, const char *y);
 int dns_name_endswith(const char *name, const char *suffix);
 
diff --git a/src/test/test-dns-domain.c b/src/test/test-dns-domain.c
index 9a5a2a1c23..31e110cf0d 100644
--- a/src/test/test-dns-domain.c
+++ b/src/test/test-dns-domain.c
@@ -160,6 +160,38 @@ static void test_dns_name_equal(void) {
         test_dns_name_equal_one("..", "..", -EINVAL);
 }
 
+static void test_dns_name_between_one(const char *a, const char *b, const char *c, int ret) {
+        int r;
+
+        r = dns_name_between(a, b, c);
+        assert_se(r == ret);
+
+        r = dns_name_between(c, b, a);
+        if (ret >= 0)
+                assert_se(r == 0);
+        else
+                assert_se(r == ret);
+}
+
+static void test_dns_name_between(void) {
+        /* see https://tools.ietf.org/html/rfc4034#section-6.1
+           Note that we use "\033.z.example" in stead of "\001.z.example" as we
+           consider the latter invalid */
+        test_dns_name_between_one("example", "a.example", "yljkjljk.a.example", true);
+        test_dns_name_between_one("a.example", "yljkjljk.a.example", "Z.a.example", true);
+        test_dns_name_between_one("yljkjljk.a.example", "Z.a.example", "zABC.a.EXAMPLE", true);
+        test_dns_name_between_one("Z.a.example", "zABC.a.EXAMPLE", "z.example", true);
+        test_dns_name_between_one("zABC.a.EXAMPLE", "z.example", "\\033.z.example", true);
+        test_dns_name_between_one("z.example", "\\033.z.example", "*.z.example", true);
+        test_dns_name_between_one("\\033.z.example", "*.z.example", "\\200.z.example", true);
+        test_dns_name_between_one("*.z.example", "\\200.z.example", "example", true);
+        test_dns_name_between_one("\\200.z.example", "example", "a.example", true);
+
+        test_dns_name_between_one("example", "a.example", "example", -EINVAL);
+        test_dns_name_between_one("example", "example", "yljkjljk.a.example", false);
+        test_dns_name_between_one("example", "yljkjljk.a.example", "yljkjljk.a.example", false);
+}
+
 static void test_dns_name_endswith_one(const char *a, const char *b, int ret) {
         assert_se(dns_name_endswith(a, b) == ret);
 }
@@ -225,6 +257,7 @@ int main(int argc, char *argv[]) {
         test_dns_name_normalize();
         test_dns_name_equal();
         test_dns_name_endswith();
+        test_dns_name_between();
         test_dns_name_root();
         test_dns_name_single_label();
         test_dns_name_reverse();