diff --git a/docs/modules/servers/partials/configure/smtp.adoc b/docs/modules/servers/partials/configure/smtp.adoc
index 788f205b7bf..f6d826a2f82 100644
--- a/docs/modules/servers/partials/configure/smtp.adoc
+++ b/docs/modules/servers/partials/configure/smtp.adoc
@@ -99,6 +99,16 @@ channels.
 | This is an optional tag, defaults to true. If false, AUTH PLAIN and AUTH LOGIN will not be exposed. This setting
 can be used to enforce strong authentication mechanisms.
 
+| auth.required
+| Authentication is required to send emails. Adapted for submission ports.
+
+Note that if false (legacy value and default for backward compatibility) then unauthenticated senders are allowed but
+limited by sender verification (prevent spoofing) and relaying limits (must be authenticated to relay).
+
+We encourage setting this value to true on submission ports (465 + 587).
+
+Please note that `authorizedAddresses` are considered authenticated.
+
 | auth.oidc.oidcConfigurationURL
 | Provide OIDC url address for information to user. Only configure this when you want to authenticate SMTP server using a OIDC provider.
 
@@ -165,6 +175,8 @@ Backward compatibility is provided and thus the following values are supported:
  - `true`: act as `strict`
  - `false`: act as `disabled`
 
+Please note that this parameter only intend to prevent spoofing, and still allow unauthenticated remote users (that do not use local identity) to send email to local users.
+
 | maxmessagesize
 | This is an optional tag with a non-negative integer body.  It specifies the maximum
 size, in kbytes, of any message that will be transmitted by this SMTP server.  It is a service-wide, as opposed to
diff --git a/protocols/lmtp/src/test/java/org/apache/james/protocols/lmtp/LMTPConfigurationImpl.java b/protocols/lmtp/src/test/java/org/apache/james/protocols/lmtp/LMTPConfigurationImpl.java
index 4f874e011a1..c81959b0679 100644
--- a/protocols/lmtp/src/test/java/org/apache/james/protocols/lmtp/LMTPConfigurationImpl.java
+++ b/protocols/lmtp/src/test/java/org/apache/james/protocols/lmtp/LMTPConfigurationImpl.java
@@ -31,8 +31,9 @@ public LMTPConfigurationImpl() {
     }
 
     @Override
-    public SenderVerificationMode verifyIdentity() {
-        return SenderVerificationMode.DISABLED;
+    public SenderVerificationConfiguration senderVerificationConfiguration() {
+        boolean allowUnauthenticatedSender = true;
+        return new SenderVerificationConfiguration(SenderVerificationMode.DISABLED, allowUnauthenticatedSender);
     }
 
     @Override
diff --git a/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfiguration.java b/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfiguration.java
index 10bffd7fea5..a0eb940633e 100644
--- a/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfiguration.java
+++ b/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfiguration.java
@@ -37,12 +37,15 @@
  *
  */
 public interface SMTPConfiguration extends ProtocolConfiguration {
+    record SenderVerificationConfiguration(SenderVerificationMode mode, boolean allowUnauthenticatedSender) {
+
+    }
+
     enum SenderVerificationMode {
         STRICT,
         RELAXED,
         DISABLED;
 
-        // TODO unit tests
         public static SenderVerificationMode parse(String value) {
             return switch (value.toLowerCase(Locale.US).trim()) {
                 case "true", "strict" -> STRICT;
@@ -77,7 +80,7 @@ public static SenderVerificationMode parse(String value) {
      */
     boolean isAuthAnnounced(String remoteIP, boolean tlsStarted);
 
-    SenderVerificationMode verifyIdentity();
+    SenderVerificationConfiguration senderVerificationConfiguration();
     
     /**
      * Returns whether the remote server needs to send a HELO/EHLO
diff --git a/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfigurationImpl.java b/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfigurationImpl.java
index 8da9de699d9..3890210d72c 100644
--- a/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfigurationImpl.java
+++ b/protocols/smtp/src/main/java/org/apache/james/protocols/smtp/SMTPConfigurationImpl.java
@@ -39,8 +39,9 @@ public SMTPConfigurationImpl() {
     }
 
     @Override
-    public SenderVerificationMode verifyIdentity() {
-        return SenderVerificationMode.STRICT;
+    public SenderVerificationConfiguration senderVerificationConfiguration() {
+        boolean allowUnauthenticatedSender = true;
+        return new SenderVerificationConfiguration(SenderVerificationMode.STRICT, allowUnauthenticatedSender);
     }
 
     @Override
diff --git a/server/apps/distributed-app/sample-configuration/smtpserver.xml b/server/apps/distributed-app/sample-configuration/smtpserver.xml
index 11175466465..41f66dc3180 100644
--- a/server/apps/distributed-app/sample-configuration/smtpserver.xml
+++ b/server/apps/distributed-app/sample-configuration/smtpserver.xml
@@ -89,6 +89,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
@@ -136,6 +137,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
diff --git a/server/apps/jpa-app/sample-configuration/smtpserver.xml b/server/apps/jpa-app/sample-configuration/smtpserver.xml
index cd8b82c104e..aa69f74f1cd 100644
--- a/server/apps/jpa-app/sample-configuration/smtpserver.xml
+++ b/server/apps/jpa-app/sample-configuration/smtpserver.xml
@@ -86,6 +86,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
@@ -133,6 +134,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
diff --git a/server/apps/memory-app/sample-configuration/smtpserver.xml b/server/apps/memory-app/sample-configuration/smtpserver.xml
index cd8b82c104e..aa69f74f1cd 100644
--- a/server/apps/memory-app/sample-configuration/smtpserver.xml
+++ b/server/apps/memory-app/sample-configuration/smtpserver.xml
@@ -86,6 +86,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
@@ -133,6 +134,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
diff --git a/server/apps/postgres-app/sample-configuration/smtpserver.xml b/server/apps/postgres-app/sample-configuration/smtpserver.xml
index cd8b82c104e..aa69f74f1cd 100644
--- a/server/apps/postgres-app/sample-configuration/smtpserver.xml
+++ b/server/apps/postgres-app/sample-configuration/smtpserver.xml
@@ -86,6 +86,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
@@ -133,6 +134,7 @@
             <announce>forUnauthorizedAddresses</announce>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
+            <required>true</required>
             <!-- Sample OIDC configuration -->
             <!--
             <oidc>
diff --git a/server/mailet/integration-testing/src/main/java/org/apache/james/mailets/configuration/SmtpConfiguration.java b/server/mailet/integration-testing/src/main/java/org/apache/james/mailets/configuration/SmtpConfiguration.java
index 3bb0556257f..3640af9d2af 100644
--- a/server/mailet/integration-testing/src/main/java/org/apache/james/mailets/configuration/SmtpConfiguration.java
+++ b/server/mailet/integration-testing/src/main/java/org/apache/james/mailets/configuration/SmtpConfiguration.java
@@ -73,6 +73,7 @@ public static class Builder {
         private Optional<Boolean> startTls;
         private Optional<String> maxMessageSize;
         private Optional<SMTPConfiguration.SenderVerificationMode> verifyIndentity;
+        private Optional<Boolean> allowUnauthenticatedSender;
         private Optional<Boolean> bracketEnforcement;
         private Optional<String> authorizedAddresses;
         private final ImmutableList.Builder<HookConfigurationEntry> additionalHooks;
@@ -84,6 +85,7 @@ public Builder() {
             verifyIndentity = Optional.empty();
             maxMessageSize = Optional.empty();
             bracketEnforcement = Optional.empty();
+            allowUnauthenticatedSender = Optional.empty();
             additionalHooks = ImmutableList.builder();
         }
 
@@ -123,6 +125,11 @@ public Builder verifyIdentity() {
             return this;
         }
 
+        public Builder forbidUnauthenticatedSenders() {
+            this.allowUnauthenticatedSender = Optional.of(false);
+            return this;
+        }
+
         public Builder doNotVerifyIdentity() {
             this.verifyIndentity = Optional.of(SMTPConfiguration.SenderVerificationMode.DISABLED);
             return this;
@@ -148,6 +155,7 @@ public SmtpConfiguration build() {
                     authRequired.orElse(!AUTH_REQUIRED),
                     startTls.orElse(false),
                     bracketEnforcement.orElse(true),
+                    allowUnauthenticatedSender.orElse(true),
                     verifyIndentity.orElse(SMTPConfiguration.SenderVerificationMode.DISABLED),
                     maxMessageSize.orElse(DEFAULT_DISABLED),
                     additionalHooks.build());
@@ -162,6 +170,7 @@ public static Builder builder() {
     private final boolean authRequired;
     private final boolean startTls;
     private final boolean bracketEnforcement;
+    private final boolean allowUnauthenticatedSenders;
     private final SMTPConfiguration.SenderVerificationMode verifyIndentity;
     private final String maxMessageSize;
     private final ImmutableList<HookConfigurationEntry> additionalHooks;
@@ -170,6 +179,7 @@ private SmtpConfiguration(Optional<String> authorizedAddresses,
                               boolean authRequired,
                               boolean startTls,
                               boolean bracketEnforcement,
+                              boolean allowUnauthenticatedSenders,
                               SMTPConfiguration.SenderVerificationMode verifyIndentity,
                               String maxMessageSize,
                               ImmutableList<HookConfigurationEntry> additionalHooks) {
@@ -177,6 +187,7 @@ private SmtpConfiguration(Optional<String> authorizedAddresses,
         this.authRequired = authRequired;
         this.bracketEnforcement = bracketEnforcement;
         this.verifyIndentity = verifyIndentity;
+        this.allowUnauthenticatedSenders = allowUnauthenticatedSenders;
         this.maxMessageSize = maxMessageSize;
         this.startTls = startTls;
         this.additionalHooks = additionalHooks;
@@ -189,6 +200,7 @@ public String serializeAsXml() throws IOException {
         authorizedAddresses.ifPresent(value -> scopes.put("authorizedAddresses", value));
         scopes.put("authRequired", authRequired);
         scopes.put("verifyIdentity", verifyIndentity.toString());
+        scopes.put("forbidUnauthenticatedSenders", Boolean.toString(!allowUnauthenticatedSenders));
         scopes.put("maxmessagesize", maxMessageSize);
         scopes.put("bracketEnforcement", bracketEnforcement);
         scopes.put("startTls", startTls);
diff --git a/server/mailet/integration-testing/src/main/resources/smtpserver.xml b/server/mailet/integration-testing/src/main/resources/smtpserver.xml
index 0f94a58a454..e2a2c719fb4 100644
--- a/server/mailet/integration-testing/src/main/resources/smtpserver.xml
+++ b/server/mailet/integration-testing/src/main/resources/smtpserver.xml
@@ -38,6 +38,7 @@
         <authorizedAddresses>{{authorizedAddresses}}</authorizedAddresses>
 {{/hasAuthorizedAddresses}}
         <auth>
+            <required>{{forbidUnauthenticatedSenders}}</required>
             <requireSSL>false</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
         </auth>
@@ -79,6 +80,7 @@
         <authorizedAddresses>{{authorizedAddresses}}</authorizedAddresses>
         {{/hasAuthorizedAddresses}}
         <auth>
+            <required>{{forbidUnauthenticatedSenders}}</required>
             <requireSSL>true</requireSSL>
             <plainAuthEnabled>true</plainAuthEnabled>
         </auth>
diff --git a/server/mailet/integration-testing/src/test/java/org/apache/james/smtp/SmtpIdentityVerificationTest.java b/server/mailet/integration-testing/src/test/java/org/apache/james/smtp/SmtpIdentityVerificationTest.java
index 5c7144691e2..b6c5c05ef74 100644
--- a/server/mailet/integration-testing/src/test/java/org/apache/james/smtp/SmtpIdentityVerificationTest.java
+++ b/server/mailet/integration-testing/src/test/java/org/apache/james/smtp/SmtpIdentityVerificationTest.java
@@ -82,6 +82,31 @@ void remoteUserCanSendEmailsToLocalUsers(@TempDir File temporaryFolder) throws E
             .sendMessage("other@domain.tld", USER);
     }
 
+    @Test
+    void remoteUserCanSendEmailsToLocalUsersWhenLocalNetwork(@TempDir File temporaryFolder) throws Exception {
+        createJamesServer(temporaryFolder, SmtpConfiguration.builder()
+            .requireAuthentication()
+            .withAutorizedAddresses("127.0.0.0/8")
+            .verifyIdentity()
+            .forbidUnauthenticatedSenders());
+
+        messageSender.connect(LOCALHOST_IP, jamesServer.getProbe(SmtpGuiceProbe.class).getSmtpPort())
+            .sendMessage("other@domain.tld", USER);
+    }
+
+    @Test
+    void remoteUserCannotSendEmailsToLocalUsersWhenUnauthorizedSendersAreRejected(@TempDir File temporaryFolder) throws Exception {
+        createJamesServer(temporaryFolder, SmtpConfiguration.builder()
+            .requireAuthentication()
+            .verifyIdentity()
+            .forbidUnauthenticatedSenders());
+
+        assertThatThrownBy(() -> messageSender.connect(LOCALHOST_IP, jamesServer.getProbe(SmtpGuiceProbe.class).getSmtpPort())
+            .sendMessage("other@domain.tld", USER))
+            .isInstanceOf(SMTPSendingException.class)
+            .hasMessageContaining("530 5.7.1 Authentication Required");
+    }
+
     @Test
     void relaxedShouldAcceptEmailsFromMXWhenLocalUsers(@TempDir File temporaryFolder) throws Exception {
         createJamesServer(temporaryFolder, SmtpConfiguration.builder()
diff --git a/server/protocols/protocols-lmtp/src/main/java/org/apache/james/lmtpserver/netty/LMTPServer.java b/server/protocols/protocols-lmtp/src/main/java/org/apache/james/lmtpserver/netty/LMTPServer.java
index f367ea7b9de..63ac70db6b4 100644
--- a/server/protocols/protocols-lmtp/src/main/java/org/apache/james/lmtpserver/netty/LMTPServer.java
+++ b/server/protocols/protocols-lmtp/src/main/java/org/apache/james/lmtpserver/netty/LMTPServer.java
@@ -102,10 +102,11 @@ public class LMTPConfigurationImpl extends LMTPConfiguration {
         protected LMTPConfigurationImpl() {
             super("JAMES Protocols Server");
         }
-        
+
         @Override
-        public SenderVerificationMode verifyIdentity() {
-            return SenderVerificationMode.DISABLED;
+        public SenderVerificationConfiguration senderVerificationConfiguration() {
+            boolean allowUnauthenticatedSender = true;
+            return new SenderVerificationConfiguration(SenderVerificationMode.DISABLED, allowUnauthenticatedSender);
         }
 
         @Override
diff --git a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/ExtendedSMTPSession.java b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/ExtendedSMTPSession.java
index 52ae853c905..e89f1457004 100644
--- a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/ExtendedSMTPSession.java
+++ b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/ExtendedSMTPSession.java
@@ -39,8 +39,9 @@ public ExtendedSMTPSession(SMTPConfiguration smtpConfiguration, ProtocolTranspor
         this.smtpConfiguration = smtpConfiguration;
     }
 
-    public SMTPConfiguration.SenderVerificationMode verifyIdentity() {
-        return smtpConfiguration.verifyIdentity();
+
+    public SMTPConfiguration.SenderVerificationConfiguration senderVerificationConfiguration() {
+        return smtpConfiguration.senderVerificationConfiguration();
     }
 
     @Override
diff --git a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/SenderAuthIdentifyVerificationHook.java b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/SenderAuthIdentifyVerificationHook.java
index 5620c9563ed..8792e3c629a 100644
--- a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/SenderAuthIdentifyVerificationHook.java
+++ b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/SenderAuthIdentifyVerificationHook.java
@@ -74,10 +74,14 @@ public SenderAuthIdentifyVerificationHook(DomainList domains, UsersRepository us
     @Override
     public HookResult doCheck(SMTPSession session, MaybeSender sender) {
         ExtendedSMTPSession nSession = (ExtendedSMTPSession) session;
-        if (nSession.verifyIdentity() == SMTPConfiguration.SenderVerificationMode.STRICT) {
+        if (!session.isRelayingAllowed() && !nSession.senderVerificationConfiguration().allowUnauthenticatedSender()) {
+            LOGGER.info("Authentication is required for sending email (sender: {})", sender.asString());
+            return AUTH_REQUIRED;
+        }
+        if (nSession.senderVerificationConfiguration().mode() == SMTPConfiguration.SenderVerificationMode.STRICT) {
             return super.doCheck(session, sender);
-        } else if (nSession.verifyIdentity() == SMTPConfiguration.SenderVerificationMode.RELAXED) {
-            return doCheckRelaxed(session, sender);
+        } else if (nSession.senderVerificationConfiguration().mode() == SMTPConfiguration.SenderVerificationMode.RELAXED) {
+            return doCheckRelaxed(nSession, sender);
         } else {
             return HookResult.DECLINED;
         }
@@ -140,8 +144,8 @@ protected boolean isSenderAllowed(Username connectedUser, Username sender) {
     @Override
     public HookResult onMessage(SMTPSession session, Mail mail) {
         ExtendedSMTPSession nSession = (ExtendedSMTPSession) session;
-        boolean shouldCheck = nSession.verifyIdentity() == SMTPConfiguration.SenderVerificationMode.STRICT ||
-            (nSession.verifyIdentity() == SMTPConfiguration.SenderVerificationMode.RELAXED && session.getUsername() != null);
+        boolean shouldCheck = nSession.senderVerificationConfiguration().mode() == SMTPConfiguration.SenderVerificationMode.STRICT ||
+            (nSession.senderVerificationConfiguration().mode() == SMTPConfiguration.SenderVerificationMode.RELAXED && session.getUsername() != null);
         if (shouldCheck) {
             try {
                 Address[] fromAddresses = mail.getMessage().getFrom();
diff --git a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/netty/SMTPServer.java b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/netty/SMTPServer.java
index 5b2d0e39870..e509ac384c7 100644
--- a/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/netty/SMTPServer.java
+++ b/server/protocols/protocols-smtp/src/main/java/org/apache/james/smtpserver/netty/SMTPServer.java
@@ -206,7 +206,7 @@ public Optional<OidcSASLConfiguration> getSaslConfiguration() {
 
     private boolean addressBracketsEnforcement = true;
 
-    private SMTPConfiguration.SenderVerificationMode verifyIdentity;
+    private SMTPConfiguration.SenderVerificationConfiguration senderVerificationConfiguration;
 
     private DNSService dns;
     private String authorizedAddresses;
@@ -267,7 +267,9 @@ public void doConfigure(HierarchicalConfiguration<ImmutableNode> configuration)
 
             addressBracketsEnforcement = configuration.getBoolean("addressBracketsEnforcement", true);
 
-            verifyIdentity = SMTPConfiguration.SenderVerificationMode.parse(configuration.getString("verifyIdentity", "strict"));
+            senderVerificationConfiguration = new SMTPConfiguration.SenderVerificationConfiguration(
+                SMTPConfiguration.SenderVerificationMode.parse(configuration.getString("verifyIdentity", "strict")),
+                !configuration.getBoolean("auth.required", false));
 
             disabledFeatures = ImmutableSet.copyOf(configuration.getStringArray("disabledFeatures"));
         }
@@ -340,12 +342,8 @@ public boolean isAuthAnnounced(String remoteIP, boolean tlsStarted) {
                 .orElse(true);
         }
 
-        /**
-         * Return true if the username and mail from must match for a authorized
-         * user
-         */
-        public SenderVerificationMode verifyIdentity() {
-            return SMTPServer.this.verifyIdentity;
+        public SenderVerificationConfiguration senderVerificationConfiguration() {
+            return senderVerificationConfiguration;
         }
 
         @Override
diff --git a/src/site/xdoc/server/config-smtp-lmtp.xml b/src/site/xdoc/server/config-smtp-lmtp.xml
index 4ffdd2f0497..2471d4c5a7b 100644
--- a/src/site/xdoc/server/config-smtp-lmtp.xml
+++ b/src/site/xdoc/server/config-smtp-lmtp.xml
@@ -109,6 +109,15 @@
 
             Please note that emails are only relayed if, and only if, the user did authenticate, or is in an authorized network,
             regardless of this option.</dd>
+        <dt><strong>auth.required</strong></dt>
+        <dd>Authentication is required to send emails. Adapted for submission ports.<br/>
+
+            Note that if false (legacy value and default for backward compatibility) then unauthenticated senders are allowed but
+            limited by sender verification (prevent spoofing) and relaying limits (must be authenticated to relay).<br/>
+
+            We encourage setting this value to true on submission ports (465 + 587).<br/>
+
+            Please note that `authorizedAddresses` are considered authenticated.</dd>
         <dt><strong>auth.requireSSL</strong></dt>
         <dd>This is an optional tag, defaults to true. If true, authentication is not advertised via capabilities on unencrypted
             channels.</dd>