diff --git a/ocaml/networkd/bin/network_server.ml b/ocaml/networkd/bin/network_server.ml
index 5044981dfe3..27016df29a9 100644
--- a/ocaml/networkd/bin/network_server.ml
+++ b/ocaml/networkd/bin/network_server.ml
@@ -218,13 +218,13 @@ let reset_state () =
   config := Network_config.read_management_conf reset_order
 
 let set_gateway_interface _dbg name =
-  (* Remove dhclient conf (if any) for the old and new gateway interfaces.
-   * This ensures that dhclient gets restarted with an updated conf file when
+  (* Mark the DHCP configuration as stale for the old and new gateway interfaces.
+   * This ensures that DHCP client will be restarted with an updated conf file when
    * necessary. *)
   ( match !config.gateway_interface with
   | Some old_iface when name <> old_iface ->
-      Dhclient.remove_conf_file name ;
-      Dhclient.remove_conf_file old_iface
+      Dhclient.set_stale name ;
+      Dhclient.set_stale old_iface
   | _ ->
       ()
   ) ;
@@ -232,13 +232,13 @@ let set_gateway_interface _dbg name =
   config := {!config with gateway_interface= Some name}
 
 let set_dns_interface _dbg name =
-  (* Remove dhclient conf (if any) for the old and new DNS interfaces.
-   * This ensures that dhclient gets restarted with an updated conf file when
+  (* Mark the DHCP configuration as stale for the old and new DNS interfaces.
+   * This ensures that DHCP client will be restarted with an updated conf file when
    * necessary. *)
   ( match !config.dns_interface with
   | Some old_iface when name <> old_iface ->
-      Dhclient.remove_conf_file name ;
-      Dhclient.remove_conf_file old_iface
+      Dhclient.set_stale name ;
+      Dhclient.set_stale old_iface
   | _ ->
       ()
   ) ;
@@ -474,6 +474,17 @@ module Interface = struct
       )
       ()
 
+  let config_to_dhcp_options config =
+    let gateway =
+      Option.fold ~none:[]
+        ~some:(fun n -> [`gateway n])
+        config.gateway_interface
+    in
+    let dns =
+      Option.fold ~none:[] ~some:(fun n -> [`dns n]) config.dns_interface
+    in
+    gateway @ dns
+
   let get_ipv4_addr dbg name =
     Debug.with_thread_associated dbg (fun () -> Ip.get_ipv4 name) ()
 
@@ -482,33 +493,27 @@ module Interface = struct
       (fun () ->
         debug "Configuring IPv4 address for %s: %s" name
           (conf |> Rpcmarshal.marshal typ_of_ipv4 |> Jsonrpc.to_string) ;
-        update_config name {(get_config name) with ipv4_conf= conf} ;
+        let previous_config = get_config name in
+        let previous = previous_config.ipv4_conf in
+        update_config name {previous_config with ipv4_conf= conf} ;
+        (* deconfigure previous *)
+        Xapi_stdext_pervasives.Pervasiveext.ignore_exn (fun () ->
+            match previous with
+            | None4 ->
+                ()
+            | DHCP4 ->
+                if conf <> DHCP4 then Dhclient.stop name
+            | Static4 _ -> (
+              match conf with Static4 _ -> () | _ -> Ip.flush_ip_addr name
+            )
+        ) ;
+        (* configure conf *)
         match conf with
         | None4 ->
-            if List.mem name (Sysfs.list ()) then (
-              if Dhclient.is_running name then ignore (Dhclient.stop name) ;
-              Ip.flush_ip_addr name
-            )
+            ()
         | DHCP4 ->
-            let gateway =
-              Option.fold ~none:[]
-                ~some:(fun n -> [`gateway n])
-                !config.gateway_interface
-            in
-            let dns =
-              Option.fold ~none:[]
-                ~some:(fun n -> [`dns n])
-                !config.dns_interface
-            in
-            if not (Dhclient.is_running name) then (* Remove any static IPs *)
-              Ip.flush_ip_addr name ;
-            let options = gateway @ dns in
-            Dhclient.ensure_running name options
+            Dhclient.ensure_running name (config_to_dhcp_options !config)
         | Static4 addrs ->
-            if Dhclient.is_running name then (
-              ignore (Dhclient.stop name) ;
-              Ip.flush_ip_addr name
-            ) ;
             (* the function is meant to be idempotent and we want to avoid
                CA-239919 *)
             let cur_addrs = Ip.get_ipv4 name in
@@ -569,53 +574,47 @@ module Interface = struct
         else (
           debug "Configuring IPv6 address for %s: %s" name
             (conf |> Rpcmarshal.marshal typ_of_ipv6 |> Jsonrpc.to_string) ;
-          update_config name {(get_config name) with ipv6_conf= conf} ;
+          let previous_config = get_config name in
+          let previous = previous_config.ipv6_conf in
+          update_config name {previous_config with ipv6_conf= conf} ;
+          (* deconfigure previous *)
+          Xapi_stdext_pervasives.Pervasiveext.ignore_exn (fun () ->
+              match previous with
+              | None6 ->
+                  ()
+              | Linklocal6 ->
+                  if conf <> Linklocal6 then Ip.flush_ip_addr ~ipv6:true name
+              | DHCP6 ->
+                  if conf <> DHCP6 then Dhclient.stop ~ipv6:true name
+              | Autoconf6 ->
+                  if conf <> Autoconf6 then (
+                    Sysctl.set_ipv6_autoconf name false ;
+                    Ip.flush_ip_addr ~ipv6:true name
+                  )
+              | Static6 _ -> (
+                match conf with
+                | Static6 _ ->
+                    ()
+                | _ ->
+                    Ip.flush_ip_addr ~ipv6:true name
+              )
+          ) ;
+          (* configure conf *)
           match conf with
           | None6 ->
-              if List.mem name (Sysfs.list ()) then (
-                if Dhclient.is_running ~ipv6:true name then
-                  ignore (Dhclient.stop ~ipv6:true name) ;
-                Sysctl.set_ipv6_autoconf name false ;
-                Ip.flush_ip_addr ~ipv6:true name
-              )
+              ()
           | Linklocal6 ->
-              if List.mem name (Sysfs.list ()) then (
-                if Dhclient.is_running ~ipv6:true name then
-                  ignore (Dhclient.stop ~ipv6:true name) ;
-                Sysctl.set_ipv6_autoconf name false ;
-                Ip.flush_ip_addr ~ipv6:true name ;
-                Ip.set_ipv6_link_local_addr name
-              )
+              Ip.set_ipv6_link_local_addr name
           | DHCP6 ->
-              let gateway =
-                Option.fold ~none:[]
-                  ~some:(fun n -> [`gateway n])
-                  !config.gateway_interface
-              in
-              let dns =
-                Option.fold ~none:[]
-                  ~some:(fun n -> [`dns n])
-                  !config.dns_interface
-              in
-              if Dhclient.is_running ~ipv6:true name then
-                ignore (Dhclient.stop ~ipv6:true name) ;
-              Sysctl.set_ipv6_autoconf name false ;
-              Ip.flush_ip_addr ~ipv6:true name ;
               Ip.set_ipv6_link_local_addr name ;
-              let options = gateway @ dns in
-              ignore (Dhclient.ensure_running ~ipv6:true name options)
+              Dhclient.ensure_running ~ipv6:true name
+                (config_to_dhcp_options !config)
           | Autoconf6 ->
-              if Dhclient.is_running ~ipv6:true name then
-                ignore (Dhclient.stop ~ipv6:true name) ;
-              Ip.flush_ip_addr ~ipv6:true name ;
               Ip.set_ipv6_link_local_addr name ;
               Sysctl.set_ipv6_autoconf name true
               (* Cannot link set down/up due to CA-89882 - IPv4 default route
-                 cleared *)
+                cleared *)
           | Static6 addrs ->
-              if Dhclient.is_running ~ipv6:true name then
-                ignore (Dhclient.stop ~ipv6:true name) ;
-              Sysctl.set_ipv6_autoconf name false ;
               (* add the link_local and clean the old one only when needed *)
               let cur_addrs =
                 let addrs = Ip.get_ipv6 name in
@@ -910,20 +909,19 @@ module Interface = struct
         List.iter
           (function
             | ( name
-              , ( {
-                    ipv4_conf
-                  ; ipv4_gateway
-                  ; ipv6_conf
-                  ; ipv6_gateway
-                  ; ipv4_routes
-                  ; dns
-                  ; mtu
-                  ; ethtool_settings
-                  ; ethtool_offload
-                  ; _
-                  } as c
-                ) ) ->
-                update_config name c ;
+              , {
+                  ipv4_conf
+                ; ipv4_gateway
+                ; ipv6_conf
+                ; ipv6_gateway
+                ; ipv4_routes
+                ; dns
+                ; mtu
+                ; ethtool_settings
+                ; ethtool_offload
+                ; persistent_i
+                } ) ->
+                exec (fun () -> set_persistent dbg name persistent_i) ;
                 exec (fun () ->
                     match dns with
                     | None ->
diff --git a/ocaml/networkd/lib/network_utils.ml b/ocaml/networkd/lib/network_utils.ml
index 8a0dbfd3f81..5e355c54873 100644
--- a/ocaml/networkd/lib/network_utils.ml
+++ b/ocaml/networkd/lib/network_utils.ml
@@ -913,20 +913,23 @@ end
 module Dhclient : sig
   type interface = string
 
-  val remove_conf_file : ?ipv6:bool -> interface -> unit
-
-  val is_running : ?ipv6:bool -> interface -> bool
+  val set_stale : ?ipv6:bool -> interface -> unit
+  (** set_stale: mark the DHCP configuration to be stale. Next call of `ensure_running`
+  will necessary trigger a restart. *)
 
   val stop : ?ipv6:bool -> interface -> unit
+  (** stop: stop the DHCP client managing [interface] if running and to unconfigure addresses. *)
 
   val ensure_running :
        ?ipv6:bool
     -> interface
     -> [> `dns of string | `gateway of string] list
     -> unit
+  (** ensure_running: ensure the DHCP client is up and running. *)
 end = struct
   type interface = string
 
+  (** pid_file: path to dhclient pidfile. *)
   let pid_file ?(ipv6 = false) interface =
     let ipv6' =
       if ipv6 then
@@ -936,6 +939,7 @@ end = struct
     in
     Printf.sprintf "/var/run/dhclient%s-%s.pid" ipv6' interface
 
+  (** lease_file: path to dhclient lease file. *)
   let lease_file ?(ipv6 = false) interface =
     let ipv6' =
       if ipv6 then
@@ -946,6 +950,7 @@ end = struct
     Filename.concat "/var/lib/xcp"
       (Printf.sprintf "dhclient%s-%s.leases" ipv6' interface)
 
+  (** conf_file: path of the dhclient configuration file. *)
   let conf_file ?(ipv6 = false) interface =
     let ipv6' =
       if ipv6 then
@@ -956,6 +961,7 @@ end = struct
     Filename.concat "/var/lib/xcp"
       (Printf.sprintf "dhclient%s-%s.conf" ipv6' interface)
 
+  (** generate_conf: return the content of dhclient configuration file. *)
   let[@warning "-27"] generate_conf ?(ipv6 = false) interface options =
     let send = "host-name = gethostname()" in
     let minimal =
@@ -993,21 +999,28 @@ end = struct
       interface send
       (String.concat ", " request)
 
+  (** read_conf_file: returns the content of dhclient configuration file. *)
   let read_conf_file ?(ipv6 = false) interface =
     let file = conf_file ~ipv6 interface in
     try Some (Xapi_stdext_unix.Unixext.string_of_file file) with _ -> None
 
+  (** write_conf_file: write updated dhclient configuration file to disk. *)
   let write_conf_file ?(ipv6 = false) interface options =
     let conf = generate_conf ~ipv6 interface options in
     Xapi_stdext_unix.Unixext.write_string_to_file
       (conf_file ~ipv6 interface)
       conf
 
-  let remove_conf_file ?(ipv6 = false) interface =
+  (** remove_conf_file: unlink the dhclient configuration file from disk. *)
+  let remove_conf_file ~ipv6 interface =
     let file = conf_file ~ipv6 interface in
     try Unix.unlink file with _ -> ()
 
+  (** start: regenerate configuration file and start DHCP client. *)
   let start ?(ipv6 = false) interface options =
+    (* create an up-to-date configuration file. *)
+    write_conf_file ~ipv6 interface options ;
+
     (* If we have a gateway interface, pass it to dhclient-script via -e *)
     (* This prevents the default route being set erroneously on CentOS *)
     (* Normally this wouldn't happen as we're not requesting routers, *)
@@ -1027,63 +1040,119 @@ end = struct
       else
         ["-e"; "PEERDNS=no"]
     in
-    write_conf_file ~ipv6 interface options ;
     let ipv6' =
       if ipv6 then
         ["-6"]
       else
         []
     in
-    call_script ~timeout:None dhclient
-      (ipv6'
-      @ gw_opt
-      @ dns_opt
-      @ [
-          "-q"
-        ; "-pf"
-        ; pid_file ~ipv6 interface
-        ; "-lf"
-        ; lease_file ~ipv6 interface
-        ; "-cf"
-        ; conf_file ~ipv6 interface
-        ; interface
-        ]
-      )
-
-  let stop ?(ipv6 = false) interface =
-    try
-      ignore
-        (call_script dhclient
-           [
-             "-r"
+    (* start dhclient *)
+    ignore
+      (call_script ~timeout:None dhclient
+         (ipv6'
+         @ gw_opt
+         @ dns_opt
+         @ [
+             "-q"
            ; "-pf"
            ; pid_file ~ipv6 interface
            ; "-lf"
            ; lease_file ~ipv6 interface
+           ; "-cf"
+           ; conf_file ~ipv6 interface
            ; interface
            ]
-        ) ;
-      Unix.unlink (pid_file ~ipv6 interface)
-    with _ -> ()
+         )
+      )
 
-  let is_running ?(ipv6 = false) interface =
+  (** is_running: returns if the DHCP client is running. *)
+  let is_running ~ipv6 interface =
     try
-      Unix.access (pid_file ~ipv6 interface) [Unix.F_OK] ;
-      true
-    with Unix.Unix_error _ -> false
+      match
+        pid_file ~ipv6 interface
+        |> Xapi_stdext_unix.Unixext.string_of_file
+        |> String.trim
+        |> int_of_string_opt
+      with
+      | Some pid ->
+          Unix.kill pid 0 ; true
+      | None ->
+          false
+    with _ -> false
+
+  (** wait_stopped: wait until DHCP client is not running.
+  Could raise Failure if it takes too long time. *)
+  let rec wait_stopped ?(count = 100) ~ipv6 interface =
+    if count = 0 then (
+      warn
+        "wait_stopped: dhclient: %s (%s): waiting for dhclient stopping is \
+         taking too long time"
+        interface
+        ( if ipv6 then
+            "ipv6"
+          else
+            "ipv4"
+        ) ;
+      failwith "wait_stopped: abording, taking too long time"
+    ) ;
+    if is_running ~ipv6 interface then (
+      Unix.sleepf 0.1 ;
+      wait_stopped ~ipv6 ~count:(count - 1) interface
+    )
+
+  (** internal_stop: stop the DHCP client process and permit to not release the addresses *)
+  let internal_stop ~ipv6 ~release interface =
+    if is_running ~ipv6 interface then (
+      Xapi_stdext_pervasives.Pervasiveext.ignore_exn (fun () ->
+          (* stop/release DHCP lease and close the DHCP client *)
+          ignore
+            (call_script dhclient
+               [
+                 ( if release then
+                     "-r"
+                   else
+                     "-x"
+                 )
+               ; "-pf"
+               ; pid_file ~ipv6 interface
+               ; "-lf"
+               ; lease_file ~ipv6 interface
+               ; interface
+               ]
+            ) ;
+          (* wait for DHCP process to be properly stopped *)
+          wait_stopped ~ipv6 interface ;
+          (* remove old configuration file *)
+          remove_conf_file ~ipv6 interface ;
+          (* remove the pid file *)
+          Unix.unlink (pid_file ~ipv6 interface)
+      ) ;
+      if release then
+        (* flush configured addresses *)
+        Ip.flush_ip_addr ~ipv6 interface
+    )
+
+  let stop ?(ipv6 = false) interface =
+    internal_stop ~ipv6 ~release:true interface
+
+  let set_stale ?(ipv6 = false) interface =
+    (* set the configuration dirty by removing the configuration file.
+     * dhclient will still run nicely, but `ensure_running` will stop/start it
+     * as the configuration will not match the (removed) configuration file.
+     *)
+    remove_conf_file ~ipv6 interface
 
   let ensure_running ?(ipv6 = false) interface options =
     if not (is_running ~ipv6 interface) then
       (* dhclient is not running, so we need to start it. *)
-      ignore (start ~ipv6 interface options)
+      start ~ipv6 interface options
     else
-      (* dhclient is running - if the config has changed, update the config file
-         and restart. *)
+      (* dhclient is running, if the config has changed, reload it. *)
       let current_conf = read_conf_file ~ipv6 interface in
       let new_conf = generate_conf ~ipv6 interface options in
       if current_conf <> Some new_conf then (
-        ignore (stop ~ipv6 interface) ;
-        ignore (start ~ipv6 interface options)
+        internal_stop ~ipv6 ~release:false interface ;
+        start ~ipv6 interface options
       )
 end