diff --git a/man/networkd.conf.xml b/man/networkd.conf.xml
index bf597cac2e..9fa925e85c 100644
--- a/man/networkd.conf.xml
+++ b/man/networkd.conf.xml
@@ -138,6 +138,13 @@
             </para></listitem>
           </varlistentry>
 
+          <varlistentry>
+            <term><option>custom</option></term>
+            <listitem><para>If <literal>DUIDType=custom</literal>, then the <literal>DUIDRawData=</literal> value will
+            used be as custom identifier. If <literal>DUIDType=custom</literal> is specified then the
+            <literal>DUIDRawData=</literal> key is mandatory. Note it applies only on DHCPv6 clients.</para></listitem>
+          </varlistentry>
+
           <varlistentry>
             <term><option>uuid</option></term>
             <listitem><para>If <literal>DUIDType=uuid</literal>, and <varname>DUIDRawData=</varname> is not set,
diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c
index a27d67a315..83fb6ce340 100644
--- a/src/libsystemd-network/dhcp-identifier.c
+++ b/src/libsystemd-network/dhcp-identifier.c
@@ -15,10 +15,11 @@
 #define USEC_2000       ((usec_t) 946684800000000) /* 2000-01-01 00:00:00 UTC */
 
 static const char * const duid_type_table[_DUID_TYPE_MAX] = {
-        [DUID_TYPE_LLT]  = "DUID-LLT",
-        [DUID_TYPE_EN]   = "DUID-EN/Vendor",
-        [DUID_TYPE_LL]   = "DUID-LL",
-        [DUID_TYPE_UUID] = "UUID",
+        [DUID_TYPE_LLT]    = "DUID-LLT",
+        [DUID_TYPE_EN]     = "DUID-EN/Vendor",
+        [DUID_TYPE_LL]     = "DUID-LL",
+        [DUID_TYPE_UUID]   = "UUID",
+        [DUID_TYPE_CUSTOM] = "Custom",
 };
 
 DEFINE_STRING_TABLE_LOOKUP_TO_STRING(duid_type, DUIDType);
diff --git a/src/libsystemd-network/dhcp-identifier.h b/src/libsystemd-network/dhcp-identifier.h
index 523dfc4a71..1ac3476157 100644
--- a/src/libsystemd-network/dhcp-identifier.h
+++ b/src/libsystemd-network/dhcp-identifier.h
@@ -17,6 +17,7 @@ typedef enum DUIDType {
         DUID_TYPE_EN        = 2,
         DUID_TYPE_LL        = 3,
         DUID_TYPE_UUID      = 4,
+        DUID_TYPE_CUSTOM    = 5,
         _DUID_TYPE_MAX,
         _DUID_TYPE_INVALID  = -EINVAL,
 } DUIDType;
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index 2f4053caad..e8d99718b3 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -212,10 +212,14 @@ static int dhcp6_client_set_duid_internal(
                         log_dhcp6_client(client, "Using DUID of type %i of incorrect length, proceeding.", duid_type);
                 }
 
-                client->duid.type = htobe16(duid_type);
-                memcpy(&client->duid.raw.data, duid, duid_len);
-                client->duid_len = sizeof(client->duid.type) + duid_len;
-
+                if (duid_type == DUID_TYPE_CUSTOM) {
+                        memcpy(&client->duid, duid, duid_len);
+                        client->duid_len = duid_len;
+                } else {
+                        client->duid.type = htobe16(duid_type);
+                        memcpy(&client->duid.raw.data, duid, duid_len);
+                        client->duid_len = sizeof(client->duid.type) + duid_len;
+                }
         } else {
                 r = dhcp_identifier_set_duid(duid_type, &client->hw_addr, client->arp_type, llt_time,
                                              client->test_mode, &client->duid, &client->duid_len);
diff --git a/src/network/networkd-dhcp-common.c b/src/network/networkd-dhcp-common.c
index 5f9ef80e3e..baf80cb644 100644
--- a/src/network/networkd-dhcp-common.c
+++ b/src/network/networkd-dhcp-common.c
@@ -1106,10 +1106,11 @@ static const char * const dhcp_option_data_type_table[_DHCP_OPTION_DATA_MAX] = {
 DEFINE_STRING_TABLE_LOOKUP(dhcp_option_data_type, DHCPOptionDataType);
 
 static const char* const duid_type_table[_DUID_TYPE_MAX] = {
-        [DUID_TYPE_LLT]  = "link-layer-time",
-        [DUID_TYPE_EN]   = "vendor",
-        [DUID_TYPE_LL]   = "link-layer",
-        [DUID_TYPE_UUID] = "uuid",
+        [DUID_TYPE_LLT]    = "link-layer-time",
+        [DUID_TYPE_EN]     = "vendor",
+        [DUID_TYPE_LL]     = "link-layer",
+        [DUID_TYPE_UUID]   = "uuid",
+        [DUID_TYPE_CUSTOM] = "custom",
 };
 DEFINE_PRIVATE_STRING_TABLE_LOOKUP_FROM_STRING(duid_type, DUIDType);
 
diff --git a/src/network/networkd-dhcp6.c b/src/network/networkd-dhcp6.c
index 00c767e1fb..e0f0850898 100644
--- a/src/network/networkd-dhcp6.c
+++ b/src/network/networkd-dhcp6.c
@@ -555,6 +555,11 @@ static int dhcp6_set_identifier(Link *link, sd_dhcp6_client *client) {
         }
 
         duid = link_get_dhcp6_duid(link);
+
+        if (duid->type == DUID_TYPE_CUSTOM && duid->raw_data_len == 0)
+                return log_link_debug_errno(link, SYNTHETIC_ERRNO(EINVAL),
+                                            "DHCPv6 CLIENT: Missing DUID Raw Data as duid type set to 'custom': %m");
+
         if (duid->type == DUID_TYPE_LLT && duid->raw_data_len == 0)
                 r = sd_dhcp6_client_set_duid_llt(client, duid->llt_time);
         else