diff --git a/src/libnm-glib-aux/nm-inet-utils.h b/src/libnm-glib-aux/nm-inet-utils.h
index 043ad79930..b730bda06d 100644
--- a/src/libnm-glib-aux/nm-inet-utils.h
+++ b/src/libnm-glib-aux/nm-inet-utils.h
@@ -254,15 +254,19 @@ gboolean nm_ip6_addr_is_ula(const struct in6_addr *address);
 
 /*****************************************************************************/
 
-#define NM_IPV4LL_NETWORK ((in_addr_t) htonl(0xA9FE0000lu))
-#define NM_IPV4LL_NETMASK ((in_addr_t) htonl(0xFFFF0000lu))
+#define NM_IPV4LL_NETWORK   ((in_addr_t) htonl(0xA9FE0000lu)) /* 169.254.0.0 */
+#define NM_IPV4LL_NETMASK   ((in_addr_t) htonl(0xFFFF0000lu)) /* 255.255.0.0 */
+#define NM_IPV4LO_NETWORK   ((in_addr_t) htonl(0x7F000000lu)) /* 127.0.0.0 */
+#define NM_IPV4LO_NETMASK   ((in_addr_t) htonl(0xFF000000lu)) /* 255.0.0.0 */
+#define NM_IPV4LO_PREFIXLEN 8
+#define NM_IPV4LO_ADDR1     ((in_addr_t) htonl(0x7F000001lu)) /* 127.0.0.1 */
 
 static inline gboolean
 nm_ip4_addr_is_loopback(in_addr_t addr)
 {
     /* There is also IN_LOOPBACK() in <linux/in.h>, but there the
      * argument is in host order not `in_addr_t`. */
-    return (addr & htonl(0xFF000000u)) == htonl(0x7F000000u);
+    return (addr & NM_IPV4LO_NETMASK) == NM_IPV4LO_NETWORK;
 }
 
 static inline gboolean
diff --git a/src/libnm-glib-aux/tests/test-shared-general.c b/src/libnm-glib-aux/tests/test-shared-general.c
index 5d9072e177..a49bbe0a20 100644
--- a/src/libnm-glib-aux/tests/test-shared-general.c
+++ b/src/libnm-glib-aux/tests/test-shared-general.c
@@ -259,6 +259,10 @@ test_nm_ip4_addr_is_loopback(void)
     g_assert(!nm_ip4_addr_is_loopback(nmtst_inet4_from_string("126.5.0.1")));
     g_assert(!nm_ip4_addr_is_loopback(nmtst_inet4_from_string("128.5.0.1")));
     g_assert(!nm_ip4_addr_is_loopback(nmtst_inet4_from_string("129.5.0.1")));
+    g_assert_cmpint(nmtst_inet4_from_string("127.0.0.0"), ==, NM_IPV4LO_NETWORK);
+    g_assert_cmpint(nmtst_inet4_from_string("127.0.0.1"), ==, NM_IPV4LO_ADDR1);
+    g_assert_cmpint(nmtst_inet4_from_string("255.0.0.0"), ==, NM_IPV4LO_NETMASK);
+    g_assert_cmpint(nm_ip4_addr_netmask_to_prefix(NM_IPV4LO_NETMASK), ==, NM_IPV4LO_PREFIXLEN);
 }
 
 /*****************************************************************************/