diff --git a/include/haproxy/protocol-t.h b/include/haproxy/protocol-t.h
index 838c7c31c..42230acb8 100644
--- a/include/haproxy/protocol-t.h
+++ b/include/haproxy/protocol-t.h
@@ -74,8 +74,12 @@ enum proto_type {
  * permanent confusion between domain and family. Here's how it works:
  *   - the domain defines the format of addresses (e.g. sockaddr_in etc),
  *     it is passed as the first argument to socket()
- *   - the family is part of the address and is stored in receivers, servers
- *     and everywhere there is an address. It's also a proto_fam selector.
+ *   - the socket family is part of the address and is stored in receivers,
+ *     servers and everywhere there is an address. It's also a proto_fam
+ *     selector.
+ *   - the real family is the one passed to bind() and connect() to map
+ *     custom families to their real equivalent one.
+ *
  * Domains are often PF_xxx though man 2 socket on Linux quotes 4.x BSD's man
  * that says AF_* can be used everywhere. At least it tends to keep the code
  * clearer about the intent. In HAProxy we're defining new address families
@@ -86,6 +90,7 @@ struct proto_fam {
 	char name[PROTO_NAME_LEN];                      /* family name, zero-terminated */
 	int sock_domain;				/* socket domain, as passed to socket()   */
 	sa_family_t sock_family;			/* socket family, for sockaddr */
+	sa_family_t real_family;			/* the socket family passed to syscalls */
 	ushort l3_addrlen;				/* layer3 address length, used by hashes */
 	socklen_t sock_addrlen;				/* socket address length, used by bind() */
 	/* 4-bytes hole here */
diff --git a/include/haproxy/protocol.h b/include/haproxy/protocol.h
index a6c50ceb5..475ac5ebb 100644
--- a/include/haproxy/protocol.h
+++ b/include/haproxy/protocol.h
@@ -113,6 +113,17 @@ static inline const struct proto_fam *proto_fam_lookup(int ss_family)
 	return NULL;
 }
 
+/* returns either the real family when known or AF_UNSPEC for non-existing
+ * families. Note that real families that contain a custom value will be
+ * returned as-is. This aims at simplifying address validation tests everywhere.
+ */
+static inline int real_family(int ss_family)
+{
+	const struct proto_fam *fam = proto_fam_lookup(ss_family);
+
+	return fam ? fam->real_family : AF_UNSPEC;
+}
+
 #endif /* _HAPROXY_PROTOCOL_H */
 
 /*
diff --git a/src/proto_rhttp.c b/src/proto_rhttp.c
index e831a5936..ccd56cf85 100644
--- a/src/proto_rhttp.c
+++ b/src/proto_rhttp.c
@@ -24,6 +24,7 @@ struct proto_fam proto_fam_rhttp = {
 	.name = "rhttp",
 	.sock_domain = AF_INET,
 	.sock_family = AF_CUST_RHTTP_SRV,
+	.real_family = AF_CUST_RHTTP_SRV,
 	.bind = rhttp_bind_receiver,
 };
 
diff --git a/src/proto_sockpair.c b/src/proto_sockpair.c
index 69ab45cfc..00f817f6a 100644
--- a/src/proto_sockpair.c
+++ b/src/proto_sockpair.c
@@ -52,6 +52,7 @@ struct proto_fam proto_fam_sockpair = {
 	.name = "sockpair",
 	.sock_domain = AF_UNIX,
 	.sock_family = AF_CUST_SOCKPAIR,
+	.real_family = AF_CUST_SOCKPAIR,
 	.sock_addrlen = sizeof(struct sockaddr_un),
 	.l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),
 	.addrcmp = NULL,
diff --git a/src/sock_inet.c b/src/sock_inet.c
index 028ffaa68..07364f02a 100644
--- a/src/sock_inet.c
+++ b/src/sock_inet.c
@@ -35,6 +35,7 @@ struct proto_fam proto_fam_inet4 = {
 	.name = "inet4",
 	.sock_domain = PF_INET,
 	.sock_family = AF_INET,
+	.real_family = AF_INET,
 	.sock_addrlen = sizeof(struct sockaddr_in),
 	.l3_addrlen = 32/8,
 	.addrcmp = sock_inet4_addrcmp,
@@ -48,6 +49,7 @@ struct proto_fam proto_fam_inet6 = {
 	.name = "inet6",
 	.sock_domain = PF_INET6,
 	.sock_family = AF_INET6,
+	.real_family = AF_INET6,
 	.sock_addrlen = sizeof(struct sockaddr_in6),
 	.l3_addrlen = 128/8,
 	.addrcmp = sock_inet6_addrcmp,
diff --git a/src/sock_unix.c b/src/sock_unix.c
index 0f9bc9a38..510b4240b 100644
--- a/src/sock_unix.c
+++ b/src/sock_unix.c
@@ -40,6 +40,7 @@ struct proto_fam proto_fam_unix = {
 	.name = "unix",
 	.sock_domain = PF_UNIX,
 	.sock_family = AF_UNIX,
+	.real_family = AF_UNIX,
 	.sock_addrlen = sizeof(struct sockaddr_un),
 	.l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),
 	.addrcmp = sock_unix_addrcmp,