diff --git a/include/netdb.h b/include/netdb.h
index 016b8ca0f58..969d18dcfc1 100644
--- a/include/netdb.h
+++ b/include/netdb.h
@@ -214,7 +214,7 @@ struct servent
   FAR char  *s_name;       /* Official name of the service. */
   FAR char **s_aliases;    /* A pointer to an array of pointers to
                             * alternative service names, terminated by a
-                            * null pointer.  */
+                            * null pointer. */
   int        s_port;       /* The port number at which the service resides,
                             * in network byte order. */
   FAR char  *s_proto;      /* The name of the protocol to use when
@@ -223,15 +223,15 @@ struct servent
 
 struct addrinfo
 {
-  int        ai_flags;     /* Input flags.  */
-  int        ai_family;    /* Address family of socket.  */
-  int        ai_socktype;  /* Socket type.  */
-  int        ai_protocol;  /* Protocol of socket.  */
-  socklen_t  ai_addrlen;   /* Length of socket address.  */
+  int        ai_flags;     /* Input flags. */
+  int        ai_family;    /* Address family of socket. */
+  int        ai_socktype;  /* Socket type. */
+  int        ai_protocol;  /* Protocol of socket. */
+  socklen_t  ai_addrlen;   /* Length of socket address. */
 
-  FAR struct sockaddr *ai_addr;      /* Socket address of socket.  */
-  FAR char            *ai_canonname; /* Canonical name of service location.  */
-  FAR struct addrinfo *ai_next;      /* Pointer to next in list.  */
+  FAR struct sockaddr *ai_addr;      /* Socket address of socket. */
+  FAR char            *ai_canonname; /* Canonical name of service location. */
+  FAR struct addrinfo *ai_next;      /* Pointer to next in list. */
 };
 
 /****************************************************************************
diff --git a/include/netinet/in.h b/include/netinet/in.h
index b4d9d1ef025..c4338772497 100644
--- a/include/netinet/in.h
+++ b/include/netinet/in.h
@@ -84,15 +84,21 @@
 #define IPPROTO_MPLS          137  /* MPLS in IP (RFC 4023) */
 #define IPPROTO_RAW           255  /* Raw IP packets */
 
-/* Values for option_name argument of getsockopt() or setsockopt() */
+/* SOL_IPV6 protocol-level socket options.  Values for option_name argument
+ * of getsockopt() or setsockopt()
+ */
 
 #define IPV6_JOIN_GROUP       (__SO_PROTOCOL + 1) /* Join a multicast group */
 #define IPV6_LEAVE_GROUP      (__SO_PROTOCOL + 2) /* Quit a multicast group */
 #define IPV6_MULTICAST_HOPS   (__SO_PROTOCOL + 3) /* Multicast hop limit */
-#define IPV6_MULTICAST_IF     (__SO_PROTOCOL + 4) /* Interface to use for outgoing multicast packets */
-#define IPV6_MULTICAST_LOOP   (__SO_PROTOCOL + 5) /* Multicast packets are delivered back to the local application */
+#define IPV6_MULTICAST_IF     (__SO_PROTOCOL + 4) /* Interface to use for
+                                                   * outgoing multicast packets */
+#define IPV6_MULTICAST_LOOP   (__SO_PROTOCOL + 5) /* Multicast packets are
+                                                   * delivered back to the local
+                                                   * application */
 #define IPV6_UNICAST_HOPS     (__SO_PROTOCOL + 6) /* Unicast hop limit */
-#define IPV6_V6ONLY           (__SO_PROTOCOL + 7) /* Restrict AF_INET6 socket to IPv6 communications only */
+#define IPV6_V6ONLY           (__SO_PROTOCOL + 7) /* Restrict AF_INET6 socket
+                                                   * to IPv6 communications only */
 
 /* Values used with SIOCSIFMCFILTER and SIOCGIFMCFILTER ioctl's */
 
@@ -106,9 +112,12 @@
 
 /* Special values of in_addr_t */
 
-#define INADDR_ANY            ((in_addr_t)0x00000000) /* Address to accept any incoming messages */
-#define INADDR_BROADCAST      ((in_addr_t)0xffffffff) /* Address to send to all hosts */
-#define INADDR_NONE           ((in_addr_t)0xffffffff) /* Address indicating an error return */
+#define INADDR_ANY            ((in_addr_t)0x00000000) /* Address to accept any
+                                                       * incoming messages */
+#define INADDR_BROADCAST      ((in_addr_t)0xffffffff) /* Address to send to
+                                                       * all hosts */
+#define INADDR_NONE           ((in_addr_t)0xffffffff) /* Address indicating an
+                                                       * error return */
 #define INADDR_LOOPBACK       ((in_addr_t)0x7f000001) /* Inet 127.0.0.1.  */
 
 /* Special initializer for in6_addr_t */
@@ -155,6 +164,8 @@
  * Public Type Definitions
  ****************************************************************************/
 
+/* IPv4/IPv6 port number */
+
 typedef uint16_t in_port_t;
 
 /* IPv4 Internet address */
@@ -169,7 +180,7 @@ struct in_addr
 struct sockaddr_in
 {
   sa_family_t     sin_family;       /* Address family: AF_INET */
-  uint16_t        sin_port;         /* Port in network byte order */
+  in_port_t       sin_port;         /* Port in network byte order */
   struct in_addr  sin_addr;         /* Internet address */
 };
 
@@ -194,6 +205,8 @@ struct sockaddr_in6
   uint32_t        sin6_scope_id;    /* Set of interfaces for a scope */
 };
 
+/* Used with certain IPv6 socket options */
+
 struct ipv6_mreq
 {
   struct in6_addr ipv6mr_multiaddr; /* IPv6 multicast address of group */