diff --git a/rust/connlib/clients/shared/src/messages.rs b/rust/connlib/clients/shared/src/messages.rs
index a317808e4..db1013f6d 100644
--- a/rust/connlib/clients/shared/src/messages.rs
+++ b/rust/connlib/clients/shared/src/messages.rs
@@ -297,6 +297,199 @@ mod test {
         assert_eq!(m, ingress_message);
     }
 
+    #[test]
+    fn messages_ignore_additional_fields() {
+        let m = PhoenixMessage::new_message(
+            "client",
+            IngressMessages::Init(InitClient {
+                interface: Interface {
+                    ipv4: "100.72.112.111".parse().unwrap(),
+                    ipv6: "fd00:2021:1111::13:efb9".parse().unwrap(),
+                    upstream_dns: vec![],
+                },
+                resources: vec![
+                    ResourceDescription::Cidr(ResourceDescriptionCidr {
+                        id: "73037362-715d-4a83-a749-f18eadd970e6".parse().unwrap(),
+                        address: "172.172.0.0/16".parse().unwrap(),
+                        name: "172.172.0.0/16".to_string(),
+                    }),
+                    ResourceDescription::Dns(ResourceDescriptionDns {
+                        id: "03000143-e25e-45c7-aafb-144990e57dcd".parse().unwrap(),
+                        address: "gitlab.mycorp.com".to_string(),
+                        name: "gitlab.mycorp.com".to_string(),
+                    }),
+                ],
+            }),
+            None,
+        );
+        let message = r#"{
+            "event": "init",
+            "payload": {
+                "interface": {
+                    "ipv4": "100.72.112.111",
+                    "ipv6": "fd00:2021:1111::13:efb9",
+                    "upstream_dns": [],
+                    "extra_config": "foo"
+                },
+                "resources": [
+                    {
+                        "address": "172.172.0.0/16",
+                        "id": "73037362-715d-4a83-a749-f18eadd970e6",
+                        "name": "172.172.0.0/16",
+                        "type": "cidr",
+                        "not": "relevant"
+                    },
+                    {
+                        "address": "gitlab.mycorp.com",
+                        "id": "03000143-e25e-45c7-aafb-144990e57dcd",
+                        "ipv4": "100.126.44.50",
+                        "ipv6": "fd00:2021:1111::e:7758",
+                        "name": "gitlab.mycorp.com",
+                        "type": "dns",
+                        "not": "relevant"
+                    }
+                ]
+            },
+            "ref": null,
+            "topic": "client"
+        }"#;
+        let ingress_message: PhoenixMessage<IngressMessages, ReplyMessages> =
+            serde_json::from_str(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn messages_ignore_additional_bool_fields() {
+        let m = PhoenixMessage::new_message(
+            "client",
+            IngressMessages::Init(InitClient {
+                interface: Interface {
+                    ipv4: "100.72.112.111".parse().unwrap(),
+                    ipv6: "fd00:2021:1111::13:efb9".parse().unwrap(),
+                    upstream_dns: vec![],
+                },
+                resources: vec![],
+            }),
+            None,
+        );
+        let message = r#"{
+            "event": "init",
+            "payload": {
+                "interface": {
+                    "ipv4": "100.72.112.111",
+                    "ipv6": "fd00:2021:1111::13:efb9",
+                    "upstream_dns": [],
+                    "additional": true
+                },
+                "resources": []
+            },
+            "ref": null,
+            "topic": "client"
+        }"#;
+        let ingress_message: PhoenixMessage<IngressMessages, ReplyMessages> =
+            serde_json::from_str(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn messages_ignore_additional_number_fields() {
+        let m = PhoenixMessage::new_message(
+            "client",
+            IngressMessages::Init(InitClient {
+                interface: Interface {
+                    ipv4: "100.72.112.111".parse().unwrap(),
+                    ipv6: "fd00:2021:1111::13:efb9".parse().unwrap(),
+                    upstream_dns: vec![],
+                },
+                resources: vec![],
+            }),
+            None,
+        );
+        let message = r#"{
+            "event": "init",
+            "payload": {
+                "interface": {
+                    "ipv4": "100.72.112.111",
+                    "ipv6": "fd00:2021:1111::13:efb9",
+                    "upstream_dns": [],
+                    "additional": 0.3
+                },
+                "resources": []
+            },
+            "ref": null,
+            "topic": "client"
+        }"#;
+        let ingress_message: PhoenixMessage<IngressMessages, ReplyMessages> =
+            serde_json::from_str(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn messages_ignore_additional_object_fields() {
+        let m = PhoenixMessage::new_message(
+            "client",
+            IngressMessages::Init(InitClient {
+                interface: Interface {
+                    ipv4: "100.72.112.111".parse().unwrap(),
+                    ipv6: "fd00:2021:1111::13:efb9".parse().unwrap(),
+                    upstream_dns: vec![],
+                },
+                resources: vec![],
+            }),
+            None,
+        );
+        let message = r#"{
+            "event": "init",
+            "payload": {
+                "interface": {
+                    "ipv4": "100.72.112.111",
+                    "ipv6": "fd00:2021:1111::13:efb9",
+                    "upstream_dns": [],
+                    "additional": { "ignored": "field" }
+                },
+                "resources": []
+            },
+            "ref": null,
+            "topic": "client"
+        }"#;
+        let ingress_message: PhoenixMessage<IngressMessages, ReplyMessages> =
+            serde_json::from_str(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn messages_ignore_additional_array_fields() {
+        let m = PhoenixMessage::new_message(
+            "client",
+            IngressMessages::Init(InitClient {
+                interface: Interface {
+                    ipv4: "100.72.112.111".parse().unwrap(),
+                    ipv6: "fd00:2021:1111::13:efb9".parse().unwrap(),
+                    upstream_dns: vec![],
+                },
+                resources: vec![],
+            }),
+            None,
+        );
+        let message = r#"{
+            "event": "init",
+            "payload": {
+                "interface": {
+                    "ipv4": "100.72.112.111",
+                    "ipv6": "fd00:2021:1111::13:efb9",
+                    "upstream_dns": [],
+                    "additional": [true, false]
+                },
+                "resources": []
+            },
+            "ref": null,
+            "topic": "client"
+        }"#;
+        let ingress_message: PhoenixMessage<IngressMessages, ReplyMessages> =
+            serde_json::from_str(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
     #[test]
     fn list_relays_message() {
         let m = PhoenixMessage::<EgressMessages, ()>::new_message(
diff --git a/rust/gateway/src/messages.rs b/rust/gateway/src/messages.rs
index 48d8c8ca9..fe90e4396 100644
--- a/rust/gateway/src/messages.rs
+++ b/rust/gateway/src/messages.rs
@@ -202,6 +202,7 @@ mod test {
         // TODO: We are just testing we can deserialize for now.
         let _: PhoenixMessage<IngressMessages, ()> = serde_json::from_str(message).unwrap();
     }
+
     #[test]
     fn init_phoenix_message() {
         let m = InitMessage::Init(InitGateway {
@@ -220,4 +221,118 @@ mod test {
         let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
         assert_eq!(m, ingress_message);
     }
+
+    #[test]
+    fn additional_fields_are_ignore() {
+        let m = InitMessage::Init(InitGateway {
+            interface: Interface {
+                ipv4: "100.115.164.78".parse().unwrap(),
+                ipv6: "fd00:2021:1111::2c:f6ab".parse().unwrap(),
+                upstream_dns: vec![],
+            },
+            config: Config {
+                ipv4_masquerade_enabled: true,
+                ipv6_masquerade_enabled: true,
+            },
+        });
+
+        let message = r#"{"event":"init","ref":null,"topic":"gateway","irrelevant":"field","payload":{"more":"info","interface":{"ipv6":"fd00:2021:1111::2c:f6ab","ipv4":"100.115.164.78"},"config":{"ipv4_masquerade_enabled":true,"ipv6_masquerade_enabled":true,"ignored":"field"}}}"#;
+        let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn additional_null_fields_are_ignored() {
+        let m = InitMessage::Init(InitGateway {
+            interface: Interface {
+                ipv4: "100.115.164.78".parse().unwrap(),
+                ipv6: "fd00:2021:1111::2c:f6ab".parse().unwrap(),
+                upstream_dns: vec![],
+            },
+            config: Config {
+                ipv4_masquerade_enabled: true,
+                ipv6_masquerade_enabled: true,
+            },
+        });
+
+        let message = r#"{"event":"init","ref":null,"topic":"gateway","payload":{"additional":null,"interface":{"ipv6":"fd00:2021:1111::2c:f6ab","ipv4":"100.115.164.78"},"config":{"ipv4_masquerade_enabled":true,"ipv6_masquerade_enabled":true}}}"#;
+        let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn additional_number_fields_are_ignored() {
+        let m = InitMessage::Init(InitGateway {
+            interface: Interface {
+                ipv4: "100.115.164.78".parse().unwrap(),
+                ipv6: "fd00:2021:1111::2c:f6ab".parse().unwrap(),
+                upstream_dns: vec![],
+            },
+            config: Config {
+                ipv4_masquerade_enabled: true,
+                ipv6_masquerade_enabled: true,
+            },
+        });
+
+        let message = r#"{"event":"init","ref":null,"topic":"gateway","payload":{"additional":0.3,"interface":{"ipv6":"fd00:2021:1111::2c:f6ab","ipv4":"100.115.164.78"},"config":{"ipv4_masquerade_enabled":true,"ipv6_masquerade_enabled":true}}}"#;
+        let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn additional_boolean_fields_are_ignored() {
+        let m = InitMessage::Init(InitGateway {
+            interface: Interface {
+                ipv4: "100.115.164.78".parse().unwrap(),
+                ipv6: "fd00:2021:1111::2c:f6ab".parse().unwrap(),
+                upstream_dns: vec![],
+            },
+            config: Config {
+                ipv4_masquerade_enabled: true,
+                ipv6_masquerade_enabled: true,
+            },
+        });
+
+        let message = r#"{"event":"init","ref":null,"topic":"gateway","payload":{"additional":true,"interface":{"ipv6":"fd00:2021:1111::2c:f6ab","ipv4":"100.115.164.78"},"config":{"ipv4_masquerade_enabled":true,"ipv6_masquerade_enabled":true}}}"#;
+        let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn additional_object_fields_are_ignored() {
+        let m = InitMessage::Init(InitGateway {
+            interface: Interface {
+                ipv4: "100.115.164.78".parse().unwrap(),
+                ipv6: "fd00:2021:1111::2c:f6ab".parse().unwrap(),
+                upstream_dns: vec![],
+            },
+            config: Config {
+                ipv4_masquerade_enabled: true,
+                ipv6_masquerade_enabled: true,
+            },
+        });
+
+        let message = r#"{"event":"init","ref":null,"topic":"gateway","payload":{"additional":{"ignored":"field"},"interface":{"ipv6":"fd00:2021:1111::2c:f6ab","ipv4":"100.115.164.78"},"config":{"ipv4_masquerade_enabled":true,"ipv6_masquerade_enabled":true}}}"#;
+        let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
+
+    #[test]
+    fn additional_array_fields_are_ignored() {
+        let m = InitMessage::Init(InitGateway {
+            interface: Interface {
+                ipv4: "100.115.164.78".parse().unwrap(),
+                ipv6: "fd00:2021:1111::2c:f6ab".parse().unwrap(),
+                upstream_dns: vec![],
+            },
+            config: Config {
+                ipv4_masquerade_enabled: true,
+                ipv6_masquerade_enabled: true,
+            },
+        });
+
+        let message = r#"{"event":"init","ref":null,"topic":"gateway","payload":{"additional":[true,false],"interface":{"ipv6":"fd00:2021:1111::2c:f6ab","ipv4":"100.115.164.78"},"config":{"ipv4_masquerade_enabled":true,"ipv6_masquerade_enabled":true}}}"#;
+        let ingress_message = serde_json::from_str::<InitMessage<InitGateway>>(message).unwrap();
+        assert_eq!(m, ingress_message);
+    }
 }