diff --git a/dhcp4relay/src/dhcp4relay.cpp b/dhcp4relay/src/dhcp4relay.cpp
index bc68509..4362460 100644
--- a/dhcp4relay/src/dhcp4relay.cpp
+++ b/dhcp4relay/src/dhcp4relay.cpp
@@ -864,7 +864,7 @@ void update_vlan_mapping(std::string vlan, bool is_add) {
     if (is_add) {
         std::string value;
         std::shared_ptr<swss::Table> vlan_intf_tbl = std::make_shared<swss::Table>(config_db.get(), CFG_VLAN_INTF_TABLE_NAME);
-        vlan_intf_tbl->hget(vlan, "vrf_name", value);
+        vlan_intf_tbl->hget(vlan, VRF_NAME_FIELD, value);
         if (value.size() <= 0) {
             /* use default instance as vrf */
             vlan_vrf_map[vlan] = "default";
@@ -1337,7 +1337,7 @@ void config_event_callback(evutil_socket_t fd, short event, void *arg) {
                    std::string value;
                    std::shared_ptr<swss::Table> dhcp_relay_tbl = std::make_shared<swss::Table>(config_db.get(),
                                                                     "DHCPV4_RELAY");
-                   dhcp_relay_tbl->hget((msg->vlan), "server_vrf", value);
+                   dhcp_relay_tbl->hget((msg->vlan), SERVER_VRF_FIELD, value);
                    if ((msg->vrf.empty()) || (value.length() != 0)) {
                        return;
                    }
@@ -1381,7 +1381,7 @@ void config_event_callback(evutil_socket_t fd, short event, void *arg) {
                         std::string value;
 
                         // Check for the presence of specific keys
-                        v4_relay_intf_tbl->hget(vlan.second.vlan, "link_selection", value);
+                        v4_relay_intf_tbl->hget(vlan.second.vlan, LINK_SELECTION_FIELD, value);
                         // Check if "link_selection" is present
                         if (value.length() > 0) {
                             // Fetch the value of "link_selection" from the database
@@ -1391,7 +1391,7 @@ void config_event_callback(evutil_socket_t fd, short event, void *arg) {
                             vlan.second.link_selection_opt.clear();
                         }
 
-                        v4_relay_intf_tbl->hget(vlan.second.vlan, "source_interface", value);
+                        v4_relay_intf_tbl->hget(vlan.second.vlan, SOURCE_INTERFACE_FIELD, value);
                         // Check if "source_interface" is present
                         if (value.length() > 0) {
                             // Fetch the value of "source_interface" from the database
diff --git a/dhcp4relay/src/dhcp4relay.h b/dhcp4relay/src/dhcp4relay.h
index 000c33c..d7565b6 100644
--- a/dhcp4relay/src/dhcp4relay.h
+++ b/dhcp4relay/src/dhcp4relay.h
@@ -27,6 +27,11 @@
 #define DHCPv4_OPTION_LIMIT 255
 #define RAWSOCKET_RECV_SIZE 1048576
 #define CLIENT_IF_PREFIX "Ethernet"
+#define VRF_NAME_FIELD "vrf_name"  // typo "vrf" caused VRF-update miss; field is "vrf_name"
+#define SERVER_VRF_FIELD "server_vrf"
+#define SOURCE_INTERFACE_FIELD "source_interface"
+#define LINK_SELECTION_FIELD "link_selection"
+#define STATE_FIELD "state"
 #define BUFFER_SIZE 9200        // TODO: change to dynamic size based on MTU
 #define MAX_DHCP_PKT_SIZE 1472  // 1500 - (IP + UDP)headers
 #define MAC_ADDR_STR_LEN 17
diff --git a/dhcp4relay/src/dhcp4relay_mgr.cpp b/dhcp4relay/src/dhcp4relay_mgr.cpp
index c5d631b..115c824 100644
--- a/dhcp4relay/src/dhcp4relay_mgr.cpp
+++ b/dhcp4relay/src/dhcp4relay_mgr.cpp
@@ -356,11 +356,11 @@ void DHCPMgr::process_relay_notification(std::deque<swss::KeyOpFieldsValuesTuple
                         getline(ss, substr, ',');
                         relay_msg->servers.push_back(substr);
                     }
-                } else if (f == "server_vrf") {
+                } else if (f == SERVER_VRF_FIELD) {
                     relay_msg->vrf = v;
-                } else if (f == "source_interface") {
+                } else if (f == SOURCE_INTERFACE_FIELD) {
                     relay_msg->source_interface = v;
-                } else if (f == "link_selection") {
+                } else if (f == LINK_SELECTION_FIELD) {
                     relay_msg->link_selection_opt = v;
                 } else if (f == "server_id_override") {
                     relay_msg->server_id_override_opt = v;
@@ -379,7 +379,7 @@ void DHCPMgr::process_relay_notification(std::deque<swss::KeyOpFieldsValuesTuple
                 std::string value;
                 std::shared_ptr<swss::DBConnector> config_db = std::make_shared<swss::DBConnector>("CONFIG_DB", 0);
                 std::shared_ptr<swss::Table> vlan_intf_tbl = std::make_shared<swss::Table>(config_db.get(), CFG_VLAN_INTF_TABLE_NAME);
-                vlan_intf_tbl->hget(vlan, "vrf_name", value);
+                vlan_intf_tbl->hget(vlan, VRF_NAME_FIELD, value);
                 if (value.size() <= 0) {
                     relay_msg->vrf = "default";
                 } else {
@@ -441,7 +441,7 @@ void DHCPMgr::process_feature_notification(std::deque<swss::KeyOpFieldsValuesTup
 
         std::string state;
         for (auto &field : kfvFieldsValues(entry)) {
-            if (fvField(field) == "state") {
+            if (fvField(field) == STATE_FIELD) {
                 state = fvValue(field);
                 break;
             }
@@ -633,7 +633,7 @@ void DHCPMgr::process_vlan_interface_notification(std::deque<swss::KeyOpFieldsVa
              vlan = key;
              vrf = "default";
              for (auto &fv : kfvFieldsValues(entry)) {
-                 if (fvField(fv) == "vrf") {
+                 if (fvField(fv) == VRF_NAME_FIELD) {
                      vrf = fvValue(fv);
                      break;
                  }
@@ -706,7 +706,7 @@ void DHCPMgr::process_dhcp_server_ipv4_notification(std::deque<swss::KeyOpFields
         if (operation == "SET") {
             std::string state;
             for (auto &fv : kfvFieldsValues(entry)) {
-                 if (fvField(fv) == "state") {
+                 if (fvField(fv) == STATE_FIELD) {
                      state = fvValue(fv);
                      break;
                  }