diff --git a/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
index 781734a189a8..72fee8d16d02 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2111.section.xml
@@ -40,6 +40,14 @@
           <link xlink:href="options.html#opt-services.sourcehut.enable">services.sourcehut</link>.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <link xlink:href="https://download.pureftpd.org/pub/ucarp/README">ucarp</link>,
+          an userspace implementation of the Common Address Redundancy
+          Protocol (CARP). Available as
+          <link xlink:href="options.html#opt-networking.ucarp.enable">networking.ucarp</link>.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
   <section xml:id="backward-incompatibilities">
diff --git a/nixos/doc/manual/release-notes/rl-2111.section.md b/nixos/doc/manual/release-notes/rl-2111.section.md
index 3a29b29f1063..1aa22b3a4b6f 100644
--- a/nixos/doc/manual/release-notes/rl-2111.section.md
+++ b/nixos/doc/manual/release-notes/rl-2111.section.md
@@ -18,6 +18,10 @@ In addition to numerous new and upgraded packages, this release has the followin
   development. Available as
   [services.sourcehut](options.html#opt-services.sourcehut.enable).
 
+* [ucarp](https://download.pureftpd.org/pub/ucarp/README), an userspace
+  implementation of the Common Address Redundancy Protocol (CARP). Available as
+  [networking.ucarp](options.html#opt-networking.ucarp.enable).
+
 ## Backward Incompatibilities
 
 * The `staticjinja` package has been upgraded from 1.0.4 to 2.0.0
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index 2938f79fb16a..1a4c2fb719dc 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -839,6 +839,7 @@
   ./services/networking/tox-node.nix
   ./services/networking/toxvpn.nix
   ./services/networking/tvheadend.nix
+  ./services/networking/ucarp.nix
   ./services/networking/unbound.nix
   ./services/networking/unifi.nix
   ./services/networking/v2ray.nix
diff --git a/nixos/modules/services/networking/ucarp.nix b/nixos/modules/services/networking/ucarp.nix
new file mode 100644
index 000000000000..9b19a19687bc
--- /dev/null
+++ b/nixos/modules/services/networking/ucarp.nix
@@ -0,0 +1,183 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.networking.ucarp;
+
+  ucarpExec = concatStringsSep " " (
+    [
+      "${cfg.package}/bin/ucarp"
+      "--interface=${cfg.interface}"
+      "--srcip=${cfg.srcIp}"
+      "--vhid=${toString cfg.vhId}"
+      "--passfile=${cfg.passwordFile}"
+      "--addr=${cfg.addr}"
+      "--advbase=${toString cfg.advBase}"
+      "--advskew=${toString cfg.advSkew}"
+      "--upscript=${cfg.upscript}"
+      "--downscript=${cfg.downscript}"
+      "--deadratio=${toString cfg.deadratio}"
+    ]
+    ++ (optional cfg.preempt "--preempt")
+    ++ (optional cfg.neutral "--neutral")
+    ++ (optional cfg.shutdown "--shutdown")
+    ++ (optional cfg.ignoreIfState "--ignoreifstate")
+    ++ (optional cfg.noMcast "--nomcast")
+    ++ (optional (cfg.extraParam != null) "--xparam=${cfg.extraParam}")
+  );
+in {
+  options.networking.ucarp = {
+    enable = mkEnableOption "ucarp, userspace implementation of CARP";
+
+    interface = mkOption {
+      type = types.str;
+      description = "Network interface to bind to.";
+      example = "eth0";
+    };
+
+    srcIp = mkOption {
+      type = types.str;
+      description = "Source (real) IP address of this host.";
+    };
+
+    vhId = mkOption {
+      type = types.ints.between 1 255;
+      description = "Virtual IP identifier shared between CARP hosts.";
+      example = 1;
+    };
+
+    passwordFile = mkOption {
+      type = types.str;
+      description = "File containing shared password between CARP hosts.";
+      example = "/run/keys/ucarp-password";
+    };
+
+    preempt = mkOption {
+      type = types.bool;
+      description = ''
+        Enable preemptive failover.
+        Thus, this host becomes the CARP master as soon as possible.
+      '';
+      default = false;
+    };
+
+    neutral = mkOption {
+      type = types.bool;
+      description = "Do not run downscript at start if the host is the backup.";
+      default = false;
+    };
+
+    addr = mkOption {
+      type = types.str;
+      description = "Virtual shared IP address.";
+    };
+
+    advBase = mkOption {
+      type = types.ints.unsigned;
+      description = "Advertisement frequency in seconds.";
+      default = 1;
+    };
+
+    advSkew = mkOption {
+      type = types.ints.unsigned;
+      description = "Advertisement skew in seconds.";
+      default = 0;
+    };
+
+    upscript = mkOption {
+      type = types.path;
+      description = ''
+        Command to run after become master, the interface name, virtual address
+        and optional extra parameters are passed as arguments.
+      '';
+      example = ''
+        pkgs.writeScript "upscript" '''
+          #!/bin/sh
+          $\{pkgs.iproute2\}/bin/ip addr add "$2"/24 dev "$1"
+        ''';
+      '';
+    };
+
+    downscript = mkOption {
+      type = types.path;
+      description = ''
+        Command to run after become backup, the interface name, virtual address
+        and optional extra parameters are passed as arguments.
+      '';
+      example = ''
+        pkgs.writeScript "downscript" '''
+          #!/bin/sh
+          $\{pkgs.iproute2\}/bin/ip addr del "$2"/24 dev "$1"
+        ''';
+      '';
+    };
+
+    deadratio = mkOption {
+      type = types.ints.unsigned;
+      description = "Ratio to consider a host as dead.";
+      default = 3;
+    };
+
+    shutdown = mkOption {
+      type = types.bool;
+      description = "Call downscript at exit.";
+      default = false;
+    };
+
+    ignoreIfState = mkOption {
+      type = types.bool;
+      description = "Ignore interface state, e.g., down or no carrier.";
+      default = false;
+    };
+
+    noMcast = mkOption {
+      type = types.bool;
+      description = "Use broadcast instead of multicast advertisements.";
+      default = false;
+    };
+
+    extraParam = mkOption {
+      type = types.nullOr types.str;
+      description = "Extra parameter to pass to the up/down scripts.";
+      default = null;
+    };
+
+    package = mkOption {
+      type = types.package;
+      description = ''
+        Package that should be used for ucarp.
+
+        Please note that the default package, pkgs.ucarp, has not received any
+        upstream updates for a long time and can be considered as unmaintained.
+      '';
+      default = pkgs.ucarp;
+      defaultText = "pkgs.ucarp";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.ucarp = {
+      description = "ucarp, userspace implementation of CARP";
+
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      serviceConfig = {
+        Type = "exec";
+        ExecStart = ucarpExec;
+
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        ProtectClock = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        MemoryDenyWriteExecute = true;
+        RestrictRealtime = true;
+      };
+    };
+  };
+
+  meta.maintainers = with lib.maintainers; [ oxzi ];
+}