diff --git a/common.c b/common.c
index fdf0db6..8ce16c4 100644
--- a/common.c
+++ b/common.c
@@ -516,12 +516,11 @@ socks_4a_start (struct socks_connector *self)
 
 	struct str *wb = &self->write_buffer;
 	str_init (wb);
-	str_append_c (wb, 4);                  // version
-	str_append_c (wb, 1);                  // connect
+	str_pack_u8 (wb, 4);                  // version
+	str_pack_u8 (wb, 1);                  // connect
 
-	str_append_c (wb, target->port >> 8);  // higher bits of port
-	str_append_c (wb, target->port);       // lower bits of port
-	str_append_data (wb, dest_ipv4, 4);    // destination address
+	str_pack_u16 (wb, target->port);      // port
+	str_append_data (wb, dest_ipv4, 4);   // destination address
 
 	if (self->username)
 		str_append (wb, self->username);
@@ -613,10 +612,10 @@ socks_5_request_start (struct socks_connector *self)
 {
 	struct socks_target *target = self->targets_iter;
 	struct str *wb = &self->write_buffer;
-	str_append_c (wb, 0x05);  // version
-	str_append_c (wb, 0x01);  // connect
-	str_append_c (wb, 0x00);  // reserved
-	str_append_c (wb, target->address.type);
+	str_pack_u8 (wb, 0x05);  // version
+	str_pack_u8 (wb, 0x01);  // connect
+	str_pack_u8 (wb, 0x00);  // reserved
+	str_pack_u8 (wb, target->address.type);
 
 	switch (target->address.type)
 	{
@@ -630,7 +629,7 @@ socks_5_request_start (struct socks_connector *self)
 		if (dlen > 255)
 			dlen = 255;
 
-		str_append_c (wb, dlen);
+		str_pack_u8 (wb, dlen);
 		str_append_data (wb, target->address.data.domain, dlen);
 		break;
 	}
@@ -639,8 +638,7 @@ socks_5_request_start (struct socks_connector *self)
 			target->address.data.ipv6, sizeof target->address.data.ipv6);
 		break;
 	}
-	str_append_c (wb, target->port >> 8);
-	str_append_c (wb, target->port);
+	str_pack_u16 (wb, target->port);
 
 	SOCKS_GO (socks_5_request_finish, 4);
 }
@@ -673,10 +671,10 @@ socks_5_userpass_start (struct socks_connector *self)
 		plen = 255;
 
 	struct str *wb = &self->write_buffer;
-	str_append_c (wb, 0x01);  // version
-	str_append_c (wb, ulen);  // username length
+	str_pack_u8 (wb, 0x01);  // version
+	str_pack_u8 (wb, ulen);  // username length
 	str_append_data (wb, self->username, ulen);
-	str_append_c (wb, plen);  // password length
+	str_pack_u8 (wb, plen);  // password length
 	str_append_data (wb, self->password, plen);
 
 	SOCKS_GO (socks_5_userpass_finish, 2);
@@ -715,11 +713,11 @@ socks_5_auth_start (struct socks_connector *self)
 	bool can_auth = self->username && self->password;
 
 	struct str *wb = &self->write_buffer;
-	str_append_c (wb, 0x05);          // version
-	str_append_c (wb, 1 + can_auth);  // number of authentication methods
-	str_append_c (wb, 0x00);          // no authentication required
+	str_pack_u8 (wb, 0x05);          // version
+	str_pack_u8 (wb, 1 + can_auth);  // number of authentication methods
+	str_pack_u8 (wb, 0x00);          // no authentication required
 	if (can_auth)
-		str_append_c (wb, 0x02);      // username/password
+		str_pack_u8 (wb, 0x02);      // username/password
 
 	SOCKS_GO (socks_5_auth_finish, 2);
 }