diff --git a/src/modules/tm/README b/src/modules/tm/README
index 445630cf346..91250b9de7c 100644
--- a/src/modules/tm/README
+++ b/src/modules/tm/README
@@ -80,6 +80,7 @@ Daniel-Constantin Mierla
               3.51. exec_time_check (int)
               3.52. reply_relay_mode (int)
               3.53. enable_uac_fr (int)
+              3.54. failover_reply_codes (string)
 
         4. Functions
 
@@ -233,57 +234,58 @@ Daniel-Constantin Mierla
    1.51. Set exec_time_check parameter
    1.52. Set reply_relay_mode parameter
    1.53. enable_uac_fr example
-   1.54. t_relay usage
-   1.55. t_relay_to_udp usage
-   1.56. t_on_failure usage
-   1.57. t_on_branch_failure usage
-   1.58. t_on_reply usage
-   1.59. t_on_branch usage
-   1.60. t_newtran usage
-   1.61. t_reply usage
-   1.62. t_send_reply usage
-   1.63. t_lookup_request usage
-   1.64. t_retransmit_reply usage
-   1.65. t_release usage
-   1.66. t_forward_nonack usage
-   1.67. t_set_fr usage
-   1.68. t_reset_fr usage
-   1.69. t_set_max_lifetime usage
-   1.70. t_reset_max_lifetime usage
-   1.71. t_set_retr usage
-   1.72. t_reset_retr usage
-   1.73. t_set_auto_inv_100 usage
-   1.74. t_branch_timeout usage
-   1.75. t_branch_replied usage
-   1.76. t_any_timeout usage
-   1.77. t_any_replied usage
-   1.78. t_grep_status usage
-   1.79. t_is_canceled usage
-   1.80. t_is_expired usage
-   1.81. t_relay_cancel usage
-   1.82. t_lookup_cancel usage
-   1.83. t_drop_replies() usage
-   1.84. t_save_lumps() usage
-   1.85. t_load_contacts usage
-   1.86. t_next_contacts usage
-   1.87. t_next_contact_flow usage
-   1.88. t_check_status usage
-   1.89. t_check_trans usage
-   1.90. t_set_disable_6xx usage
-   1.91. t_set_disable_failover usage
-   1.92. t_set_disable_internal_reply usage
-   1.93. t_replicate usage
-   1.94. t_relay_to usage
-   1.95. t_set_no_e2e_cancel_reason usage
-   1.96. t_replicate usage
-   1.97. t_use_uac_headers usage
-   1.98. t_is_retr_async_reply usage
-   1.99. t_uac_send usage
-   1.100. t_get_status_code usage
-   1.101. t_clean usage
-   1.102. event_route[tm:branch-failure:id] usage
-   1.103. event_route[tm:local-request] usage
-   1.104. event_route[tm:local-response] usage
+   1.54. Set the “failover_reply_codes” parameter
+   1.55. t_relay usage
+   1.56. t_relay_to_udp usage
+   1.57. t_on_failure usage
+   1.58. t_on_branch_failure usage
+   1.59. t_on_reply usage
+   1.60. t_on_branch usage
+   1.61. t_newtran usage
+   1.62. t_reply usage
+   1.63. t_send_reply usage
+   1.64. t_lookup_request usage
+   1.65. t_retransmit_reply usage
+   1.66. t_release usage
+   1.67. t_forward_nonack usage
+   1.68. t_set_fr usage
+   1.69. t_reset_fr usage
+   1.70. t_set_max_lifetime usage
+   1.71. t_reset_max_lifetime usage
+   1.72. t_set_retr usage
+   1.73. t_reset_retr usage
+   1.74. t_set_auto_inv_100 usage
+   1.75. t_branch_timeout usage
+   1.76. t_branch_replied usage
+   1.77. t_any_timeout usage
+   1.78. t_any_replied usage
+   1.79. t_grep_status usage
+   1.80. t_is_canceled usage
+   1.81. t_is_expired usage
+   1.82. t_relay_cancel usage
+   1.83. t_lookup_cancel usage
+   1.84. t_drop_replies() usage
+   1.85. t_save_lumps() usage
+   1.86. t_load_contacts usage
+   1.87. t_next_contacts usage
+   1.88. t_next_contact_flow usage
+   1.89. t_check_status usage
+   1.90. t_check_trans usage
+   1.91. t_set_disable_6xx usage
+   1.92. t_set_disable_failover usage
+   1.93. t_set_disable_internal_reply usage
+   1.94. t_replicate usage
+   1.95. t_relay_to usage
+   1.96. t_set_no_e2e_cancel_reason usage
+   1.97. t_replicate usage
+   1.98. t_use_uac_headers usage
+   1.99. t_is_retr_async_reply usage
+   1.100. t_uac_send usage
+   1.101. t_get_status_code usage
+   1.102. t_clean usage
+   1.103. event_route[tm:branch-failure:id] usage
+   1.104. event_route[tm:local-request] usage
+   1.105. event_route[tm:local-response] usage
 
 Chapter 1. Admin Guide
 
@@ -346,6 +348,7 @@ Chapter 1. Admin Guide
         3.51. exec_time_check (int)
         3.52. reply_relay_mode (int)
         3.53. enable_uac_fr (int)
+        3.54. failover_reply_codes (string)
 
    4. Functions
 
@@ -724,6 +727,7 @@ failure_route["serial"]
    3.51. exec_time_check (int)
    3.52. reply_relay_mode (int)
    3.53. enable_uac_fr (int)
+   3.54. failover_reply_codes (string)
 
 3.1. fr_timer (integer)
 
@@ -1764,6 +1768,24 @@ modparam("tm", "reply_relay_mode", 0)
 modparam("tm", "enable_uac_fr", 1)
 ....
 
+3.54. failover_reply_codes (string)
+
+   This parameter defines the response codes (only codes >= 300 and class
+   >= 3), which enable dns failover to continue to try next ips when
+   previous one fail. It is a list separated by colons, where you may
+   define either a single code (e.g. "code=408" would accept 408 as an
+   additional response code) or a class of responses, you want to accept
+   (e.g. "class=3" would accept everything from 300 to 999 as valid
+   response). (with default behaviour only 503 code or no response from
+   previous one will try next ip).
+
+   Default value is “”
+
+   Example 1.54. Set the “failover_reply_codes” parameter
+...
+modparam("tm", "failover_reply_codes", "code=403;code=488;class=5")
+...
+
 4. Functions
 
    4.1. t_relay([host, port])
@@ -1841,7 +1863,7 @@ modparam("tm", "enable_uac_fr", 1)
    Returns a negative value on failure -- you may still want to send a
    negative reply upstream statelessly not to leave upstream UAC in lurch.
 
-   Example 1.54. t_relay usage
+   Example 1.55. t_relay usage
 ...
 if (!t_relay())
 {
@@ -1868,7 +1890,7 @@ if (!t_relay())
    derived from the message uri (using sip specific DNS lookups), but with
    the protocol corresponding to the function name.
 
-   Example 1.55. t_relay_to_udp usage
+   Example 1.56. t_relay_to_udp usage
 ...
 if (src_ip==10.0.0.0/8)
         t_relay_to_udp("1.2.3.4", "5060"); # sent to 1.2.3.4:5060 over udp
@@ -1908,7 +1930,7 @@ else
    Meaning of the parameters is as follows:
      * failure_route - Failure route block to be called.
 
-   Example 1.56. t_on_failure usage
+   Example 1.57. t_on_failure usage
 ...
 route {
     t_on_failure("1");
@@ -1944,7 +1966,7 @@ failure_route[1] {
      * branch_failure_route - Name of the branch_failure route block to be
        called (it is prefixed internally with 'tm:branch-failure:').
 
-   Example 1.57. t_on_branch_failure usage
+   Example 1.58. t_on_branch_failure usage
 ...
 route {
     t_on_branch_failure("myroute");
@@ -1967,7 +1989,7 @@ event_route[tm:branch-failure:myroute] {
    Meaning of the parameters is as follows:
      * onreply_route - Onreply route block to be called.
 
-   Example 1.58. t_on_reply usage
+   Example 1.59. t_on_reply usage
 ...
 loadmodule "/usr/local/lib/ser/modules/nathelper.so"
 ...
@@ -1999,7 +2021,7 @@ es');
    Meaning of the parameters is as follows:
      * branch_route - branch route block to be called.
 
-   Example 1.59. t_on_branch usage
+   Example 1.60. t_on_branch usage
 ...
 route {
         t_on_branch("1");
@@ -2024,7 +2046,7 @@ branch_route[1] {
    structure. Use the tmx module function t_flush_flags() to synchronize
    the modified message flags to the already created transaction.
 
-   Example 1.60. t_newtran usage
+   Example 1.61. t_newtran usage
 ...
 if (t_newtran()) {
     xlog("the transaction has been created\n");
@@ -2056,7 +2078,7 @@ if (t_newtran()) {
      * code - Reply code number.
      * reason_phrase - Reason string.
 
-   Example 1.61. t_reply usage
+   Example 1.62. t_reply usage
 ...
 t_reply("404", "Not found");
 ...
@@ -2074,7 +2096,7 @@ t_reply("404", "Not found");
      * code - Reply code number.
      * reason - Reason string.
 
-   Example 1.62. t_send_reply usage
+   Example 1.63. t_send_reply usage
 ...
 t_send_reply("404", "Not found");
 ...
@@ -2087,7 +2109,7 @@ t_send_reply("404", "Not found");
    none was found. However this is safely (atomically) done using
    t_newtran.
 
-   Example 1.63. t_lookup_request usage
+   Example 1.64. t_lookup_request usage
 ...
 if (t_lookup_request()) {
     ...
@@ -2098,7 +2120,7 @@ if (t_lookup_request()) {
 
    Retransmits a reply sent previously by UAS transaction.
 
-   Example 1.64. t_retransmit_reply usage
+   Example 1.65. t_retransmit_reply usage
 ...
 t_retransmit_reply();
 ...
@@ -2108,7 +2130,7 @@ t_retransmit_reply();
    Remove transaction from memory (it will be first put on a wait timer to
    absorb delayed messages).
 
-   Example 1.65. t_release usage
+   Example 1.66. t_release usage
 ...
 t_release();
 ...
@@ -2122,7 +2144,7 @@ t_release();
      * ip - IP address where the message should be sent.
      * port - Port number.
 
-   Example 1.66. t_forward_nonack usage
+   Example 1.67. t_forward_nonack usage
 ...
 t_forward_nonack("1.2.3.4", "5060");
 ...
@@ -2161,7 +2183,7 @@ t_forward_nonack("1.2.3.4", "5060");
 
    See also: fr_timer, fr_inv_timer, t_reset_fr().
 
-   Example 1.67. t_set_fr usage
+   Example 1.68. t_set_fr usage
 ...
 route {
         t_set_fr(10000); # set only fr invite timeout to 10s
@@ -2188,7 +2210,7 @@ branch_route[1] {
 
    See also: fr_timer, fr_inv_timer, t_set_fr.
 
-   Example 1.68. t_reset_fr usage
+   Example 1.69. t_reset_fr usage
 ...
 route {
 ...
@@ -2214,7 +2236,7 @@ route {
 
    See also: max_inv_lifetime, max_noninv_lifetime, t_reset_max_lifetime.
 
-   Example 1.69. t_set_max_lifetime usage
+   Example 1.70. t_set_max_lifetime usage
 ...
 route {
     if (src_ip=1.2.3.4)
@@ -2236,7 +2258,7 @@ route {
 
    See also: max_inv_lifetime, max_noninv_lifetime, t_set_max_lifetime.
 
-   Example 1.70. t_reset_max_lifetime usage
+   Example 1.71. t_reset_max_lifetime usage
 ...
 route {
 ...
@@ -2271,7 +2293,7 @@ route {
 
    See also: retr_timer1, retr_timer2, t_reset_retr().
 
-   Example 1.71. t_set_retr usage
+   Example 1.72. t_set_retr usage
 ...
 route {
         t_set_retr(250, 0); # set only T1 to 250 ms
@@ -2298,7 +2320,7 @@ branch_route[1] {
 
    See also: retr_timer1, retr_timer2, t_set_retr.
 
-   Example 1.72. t_reset_retr usage
+   Example 1.73. t_reset_retr usage
 ...
 route {
 ...
@@ -2314,7 +2336,7 @@ route {
 
    See also: auto_inv_100.
 
-   Example 1.73. t_set_auto_inv_100 usage
+   Example 1.74. t_set_auto_inv_100 usage
 ...
 route {
 ...
@@ -2329,7 +2351,7 @@ route {
    timeout. It can be used from FAILURE_ROUTE and BRANCH_FAILURE_ROUTE
    event route.
 
-   Example 1.74. t_branch_timeout usage
+   Example 1.75. t_branch_timeout usage
 ...
 failure_route[0]{
         if (t_branch_timeout()){
@@ -2345,7 +2367,7 @@ failure_route[0]{
    taken into account). It can be used from failure_route and
    branch-failure event route.
 
-   Example 1.75. t_branch_replied usage
+   Example 1.76. t_branch_replied usage
 ...
 failure_route[0]{
         if (t_branch_timeout()){
@@ -2362,7 +2384,7 @@ failure_route[0]{
    Returns true if at least one of the current transactions branches did
    timeout.
 
-   Example 1.76. t_any_timeout usage
+   Example 1.77. t_any_timeout usage
 ...
 failure_route[0]{
         if (!t_branch_timeout()){
@@ -2379,7 +2401,7 @@ failure_route[0]{
    receive some reply in the past. If called from a failure or onreply
    route, the "current" reply is not taken into account.
 
-   Example 1.77. t_any_replied usage
+   Example 1.78. t_any_replied usage
 ...
 onreply_route[0]{
         if (!t_any_replied()){
@@ -2393,7 +2415,7 @@ onreply_route[0]{
    Returns true if "code" is the final reply received (or locally
    generated) in at least one of the current transactions branches.
 
-   Example 1.78. t_grep_status usage
+   Example 1.79. t_grep_status usage
 ...
 onreply_route[0]{
         if (t_grep_status("486")){
@@ -2406,7 +2428,7 @@ onreply_route[0]{
 
    Returns true if the current transaction was canceled.
 
-   Example 1.79. t_is_canceled usage
+   Example 1.80. t_is_canceled usage
 ...
 failure_route[0]{
         if (t_is_canceled()){
@@ -2420,7 +2442,7 @@ failure_route[0]{
    Returns true if the current transaction has already been expired, i.e.
    the max_inv_lifetime/max_noninv_lifetime interval has already elapsed.
 
-   Example 1.80. t_is_expired usage
+   Example 1.81. t_is_expired usage
 ...
 failure_route[0]{
         if (t_is_expired()){
@@ -2441,7 +2463,7 @@ failure_route[0]{
    CANCELs were successfully sent to the pending branches, true if the
    INVITE was not found, and false in case of any error.
 
-   Example 1.81. t_relay_cancel usage
+   Example 1.82. t_relay_cancel usage
 if (method == CANCEL) {
         if (!t_relay_cancel()) {  # implicit drop if relaying was successful,
                                   # nothing to do
@@ -2468,7 +2490,7 @@ if (method == CANCEL) {
    overwritten with the flags of the INVITE. isflagset() can be used to
    check the flags of the previously forwarded INVITE in this case.
 
-   Example 1.82. t_lookup_cancel usage
+   Example 1.83. t_lookup_cancel usage
 if (method == CANCEL) {
         if (t_lookup_cancel()) {
                 log("INVITE transaction exists");
@@ -2498,7 +2520,7 @@ if (method == CANCEL) {
    Dropping replies works only if a new branch is added to the
    transaction, or it is explicitly replied in the script!
 
-   Example 1.83. t_drop_replies() usage
+   Example 1.84. t_drop_replies() usage
 ...
 failure_route[0]{
         if (t_check_status("5[0-9][0-9]")){
@@ -2529,7 +2551,7 @@ failure_route[0]{
    The transaction must be created by t_newtran() before calling
    t_save_lumps().
 
-   Example 1.84. t_save_lumps() usage
+   Example 1.85. t_save_lumps() usage
 route {
         ...
         t_newtran();
@@ -2603,7 +2625,7 @@ failure_route[1] {
 
    This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.
 
-   Example 1.85. t_load_contacts usage
+   Example 1.86. t_load_contacts usage
 ...
 if (!t_load_contacts()) {
         sl_send_reply("500", "Server Internal Error - Cannot load contacts");
@@ -2644,7 +2666,7 @@ if (!t_load_contacts()) {
    contact_flows_avp are not anymore set. Based on that test, you can then
    use t_set_fr() function to set timers according to your needs.
 
-   Example 1.86. t_next_contacts usage
+   Example 1.87. t_next_contacts usage
 ...
 # First call after t_load_contacts() when transaction does not exist yet
 # and contacts should be available
@@ -2682,7 +2704,7 @@ if (!t_next_contacts()) {
    syslog). This function can be used from a BRANCH_FAILURE_ROUTE event
    route.
 
-   Example 1.87. t_next_contact_flow usage
+   Example 1.88. t_next_contact_flow usage
 ...
 event_route[tm:branch-failure:outbound]
 {
@@ -2705,7 +2727,7 @@ event_route[tm:branch-failure:outbound]
 
    This function can be used from ANY_ROUTE .
 
-   Example 1.88. t_check_status usage
+   Example 1.89. t_check_status usage
 ...
 if (t_check_status("(487)|(408)")) {
     log("487 or 408 negative reply\n");
@@ -2759,7 +2781,7 @@ Note
 
    See also: t_lookup_request(), t_lookup_cancel().
 
-   Example 1.89. t_check_trans usage
+   Example 1.90. t_check_trans usage
 if ( method == "CANCEL" && !t_check_trans())
         sl_reply("403", "cancel out of the blue forbidden");
 # note: in this example t_check_trans() can be replaced by t_lookup_cancel()
@@ -2774,7 +2796,7 @@ if ( method == "CANCEL" && !t_check_trans())
 
    See also: disable_6xx_block.
 
-   Example 1.90. t_set_disable_6xx usage
+   Example 1.91. t_set_disable_6xx usage
 ...
 route {
 ...
@@ -2789,7 +2811,7 @@ route {
 
    See also: use_dns_failover.
 
-   Example 1.91. t_set_disable_failover usage
+   Example 1.92. t_set_disable_failover usage
 ...
 route {
 ...
@@ -2802,7 +2824,7 @@ route {
 
    Turn off/on sending internally a SIP reply in case of relay errors.
 
-   Example 1.92. t_set_disable_internal_reply usage
+   Example 1.93. t_set_disable_internal_reply usage
 ...
 t_set_disable_internal_reply(1); # turn off sending internal reply on error
 if(!t_relay()) {
@@ -2835,7 +2857,7 @@ if(!t_relay()) {
      * hostport - address in "host:port" format. It can be given via an
        AVP.
 
-   Example 1.93. t_replicate usage
+   Example 1.94. t_replicate usage
 ...
 # sent to 1.2.3.4:5060 over tcp
 t_replicate("sip:1.2.3.4:5060;transport=tcp");
@@ -2869,7 +2891,7 @@ t_replicate_to_udp("1.2.3.4", "5060");
           + 0x02 - do not generate reply on internal error.
           + 0x04 - disable dns failover.
 
-   Example 1.94. t_relay_to usage
+   Example 1.95. t_relay_to usage
 ...
 # sent to 1.2.3.4:5060 over tcp
 t_relay_to("tcp:1.2.3.4:5060");
@@ -2895,7 +2917,7 @@ t_relay_to("0x01");
 
    See also: e2e_cancel_reason.
 
-   Example 1.95. t_set_no_e2e_cancel_reason usage
+   Example 1.96. t_set_no_e2e_cancel_reason usage
 ...
 route {
 ...
@@ -2918,7 +2940,7 @@ opying
      * onreply_route - the function returns true if an onreply route is
        set to be executed.
 
-   Example 1.96. t_replicate usage
+   Example 1.97. t_replicate usage
 ...
 if(!t_is_set("failure_route"))
     LM_DBG("no failure route will be executed for current transaction\n");
@@ -2932,7 +2954,7 @@ if(!t_is_set("failure_route"))
 
    It returns true.
 
-   Example 1.97. t_use_uac_headers usage
+   Example 1.98. t_use_uac_headers usage
 ...
 t_use_uac_headers();
 ...
@@ -2951,7 +2973,7 @@ t_use_uac_headers();
    returns true if the transaction is currently reply suspended or false
    if not.
 
-   Example 1.98. t_is_retr_async_reply usage
+   Example 1.99. t_is_retr_async_reply usage
 ...
 if (t_is_retr_async_reply()) {
         xlog("L_DBG", "Dropping retransmitted reply which is still currently sus
@@ -2976,7 +2998,7 @@ pended\n");
        Content-Type header must exist.
      * body - SIP message body (can be empty).
 
-   Example 1.99. t_uac_send usage
+   Example 1.100. t_uac_send usage
 ...
 t_uac_send("OPTIONS", "sip:alice@kamailio.org", "", "",
     "From: bob@kamailio.org;tag=2w3e\r\nTo: bob@kamailio.org", "");
@@ -2987,7 +3009,7 @@ t_uac_send("OPTIONS", "sip:alice@kamailio.org", "", "",
    Return the status code for transaction - the most relevant SIP reply
    status code, or -1 in case of error or no status code was set.
 
-   Example 1.100. t_get_status_code usage
+   Example 1.101. t_get_status_code usage
 ...
 $var(ts) = t_get_status_code();
 if($var(ts) == 500) { ... }
@@ -2998,7 +3020,7 @@ if($var(ts) == 500) { ... }
    Cleans active but very old transactions. Returns true (1). Can be
    called from any route.
 
-   Example 1.101. t_clean usage
+   Example 1.102. t_clean usage
 ...
 t_clean();
 ...
@@ -3124,7 +3146,7 @@ t_clean();
    enabled with the t_on_branch_failure function. This event_route uses
    the BRANCH_FAILURE_ROUTE route type.
 
-   Example 1.102. event_route[tm:branch-failure:id] usage
+   Example 1.103. event_route[tm:branch-failure:id] usage
 ...
 request_route {
     ...
@@ -3150,7 +3172,7 @@ event_route[tm:branch-failure:myroute] {
    The request can still be updated, i.e., changes are possible to R-URI
    ($ru), destination URI ($du) or the send socket ($fs).
 
-   Example 1.103. event_route[tm:local-request] usage
+   Example 1.104. event_route[tm:local-request] usage
 ...
 event_route [tm:local-request] {
     xlog("L_INFO", "Routing locally generated $rm to $ru\n");
@@ -3163,7 +3185,7 @@ event_route [tm:local-request] {
    Executed after the tm module sent a local generated, transaction
    stateful response.
 
-   Example 1.104. event_route[tm:local-response] usage
+   Example 1.105. event_route[tm:local-response] usage
 ...
 event_route[tm:local-response] {
     xlog("tm:local-response replied locally\n");