Nothing advertises the legacy protocols while they are off (LP-7)

While the switch is off, the answers that tell a mail app where to connect
stop offering what the switch closed, so a new phone or desktop app is not
sent to a port that is shut or a sign-in that will be refused:

- Thunderbird-style autoconfig (/mail/config-v1.1.xml and its other
  paths) and Outlook autodiscover leave out IMAP, POP3 and SMTP
  submission.
- PACC (/.well-known/user-agent-configuration.json) offers JMAP, CalDAV,
  CardDAV and WebDAV, and no IMAP, POP3, SMTP or ManageSieve. The document
  is rendered once per configuration load, so the JMAP-only version is
  rendered beside it and chosen per request; the _ua-auto-config digest in
  the suggested zone follows, since it hashes the same document.
- The suggested zone publishes _imap, _imaps, _pop3, _pop3s, _submission
  and _submissions with target "." -- "not offered", RFC 6186 section 3.4 --
  the spec's decision, rather than dropping them: a client that looks is
  told, and an automatically managed zone replaces the old records instead
  of leaving them behind.
- It also drops the TLSA records for ports 993 and 995. A TLS pin for a
  port the switch has closed advertises a service that is not there.
  Submission's 465 keeps its record: the SMTP lock keeps that port open.

The switch is read per answer, as sign-in reads it, so every node agrees
the moment it turns. Inbound mail, MX records and the JMAP, CalDAV and
CardDAV answers are untouched.

tests/e2e/legacy_protocols.py checks all four on a running server: with the
switch on they offer IMAP, POP3 and SMTP (the control); while it is off
they offer none of them and every legacy SRV name has target "."; and once
it is back on, autoconfig and the zone read as they did before. All checks
pass.

crates/common/src/config/network.rs

@@ -47,6 +47,9 @@ pub struct Network {
 #[derive(Clone)]
 pub struct NetworkInfo {
     pub pacc: Pacc,
+    /// inbuxa: the same document without IMAP, POP3, SMTP and ManageSieve,
+    /// served while legacy protocols are off (legacy-protocols LP-7).
+    pub pacc_jmap_only: Pacc,
     pub mxs: Vec<MailExchanger>,
     pub services: VecMap<ServiceProtocol, Service>,
 }
@@ -320,11 +323,26 @@ impl Network {
             }
         }
 
-        let (prefix, suffix) = serde_json::to_string(&pacc)
-            .unwrap_or_default()
-            .rsplit_once(SPLIT_HERE)
-            .map(|(prefix, suffix)| (prefix.to_string(), suffix.to_string()))
-            .unwrap();
+        let split = |pacc: &Configuration| {
+            serde_json::to_string(pacc)
+                .unwrap_or_default()
+                .rsplit_once(SPLIT_HERE)
+                .map(|(prefix, suffix)| Pacc {
+                    prefix: prefix.to_string(),
+                    suffix: suffix.to_string(),
+                })
+                .unwrap()
+        };
+        // inbuxa: legacy-protocols LP-7
+        let pacc_jmap_only = {
+            let mut pacc = pacc.clone();
+            pacc.protocols.imap = None;
+            pacc.protocols.pop3 = None;
+            pacc.protocols.smtp = None;
+            pacc.protocols.managesieve = None;
+            split(&pacc)
+        };
+        let pacc = split(&pacc);
         let mut network = Network {
             node_id: bp.node_id() as u64,
             server_name: default_hostname.to_string(),
@@ -339,7 +357,8 @@ impl Network {
             info: NetworkInfo {
                 mxs: system.mail_exchangers.into_iter().collect(),
                 services: system.services,
-                pacc: Pacc { prefix, suffix },
+                pacc,
+                pacc_jmap_only,
             },
         };
 

crates/common/src/network/autoconfig/autodiscover.rs

@@ -2,9 +2,11 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
-use crate::{Server, manager::application::Resource};
+use crate::{Server, manager::application::Resource, network::legacy::is_legacy_service};
 use quick_xml::Reader;
 use quick_xml::XmlVersion;
 use quick_xml::events::Event;
@@ -55,7 +57,12 @@ impl Server {
         let _ = writeln!(&mut config, "\t\t<Account>");
         let _ = writeln!(&mut config, "\t\t\t<AccountType>email</AccountType>");
         let _ = writeln!(&mut config, "\t\t\t<Action>settings</Action>");
+        // inbuxa: legacy-protocols LP-7
+        let legacy_off = self.legacy_protocols_off().await?;
         for (protocol, service) in &self.core.network.info.services {
+            if legacy_off && is_legacy_service(protocol) {
+                continue;
+            }
             let (protocol, ports) = match protocol {
                 ServiceProtocol::Imap => ("IMAP", [143, 993]),
                 ServiceProtocol::Pop3 => ("POP3", [110, 995]),

crates/common/src/network/autoconfig/legacy_autoconfig.rs

@@ -2,9 +2,11 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
-use crate::{Server, manager::application::Resource};
+use crate::{Server, manager::application::Resource, network::legacy::is_legacy_service};
 use registry::schema::enums::ServiceProtocol;
 use std::fmt::Write;
 use utils::url_params::UrlParams;
@@ -28,6 +30,9 @@ impl Server {
             ("%EMAILADDRESS%", default_host.as_str())
         };
 
+        // inbuxa: legacy-protocols LP-7
+        let legacy_off = self.legacy_protocols_off().await?;
+
         // Build XML response
         let mut config = String::with_capacity(1024);
         config.push_str("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
@@ -40,6 +45,9 @@ impl Server {
             "\t\t<displayShortName>{domain}</displayShortName>"
         );
         for (protocol, service) in &self.core.network.info.services {
+            if legacy_off && is_legacy_service(protocol) {
+                continue;
+            }
             let (protocol, tag, ports) = match protocol {
                 ServiceProtocol::Smtp => ("smtp", "outgoingServer", [587, 465]),
                 ServiceProtocol::Imap => ("imap", "incomingServer", [143, 993]),

crates/common/src/network/dns/records.rs

@@ -2,9 +2,15 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
-use crate::{Server, config::network::Pacc, network::dkim::generate_dkim_dns_record};
+use crate::{
+    Server,
+    config::network::Pacc,
+    network::{dkim::generate_dkim_dns_record, legacy::is_legacy_service},
+};
 use ahash::{AHashMap, AHashSet};
 use base64::{Engine, engine::general_purpose};
 use dns_update::{
@@ -33,6 +39,8 @@ impl Server {
         let mut records = Vec::new();
         let network = &self.core.network;
         let default_host = network.server_name.as_str();
+        // inbuxa: legacy-protocols LP-7
+        let legacy_off = self.legacy_protocols_off().await?;
         let domain_name = domain.name.as_str();
         let domain_name_suffix = format!(".{domain_name}");
 
@@ -193,6 +201,25 @@ impl Server {
                             ServiceProtocol::Smtp => [("submission", 587), ("submissions", 465)],
                         };
 
+                        // inbuxa: legacy-protocols LP-7. While they are off, every
+                        // name says "not offered" -- target "." (RFC 6186 section
+                        // 3.4) -- rather than vanishing, so a client that looks
+                        // is told, and an old record left in the zone is replaced.
+                        if legacy_off && is_legacy_service(protocol) {
+                            for (service_name, _) in services {
+                                records.push(NamedDnsRecord {
+                                    name: format!("_{service_name}._tcp.{domain_name}."),
+                                    record: DnsRecord::SRV(SRVRecord {
+                                        target: ".".to_string(),
+                                        priority: 0,
+                                        weight: 0,
+                                        port: 0,
+                                    }),
+                                });
+                            }
+                            continue;
+                        }
+
                         for (is_tls, (service_name, port)) in services.into_iter().enumerate() {
                             if is_tls == 1 || service.cleartext {
                                 records.push(NamedDnsRecord {
@@ -277,6 +304,14 @@ impl Server {
                     for (protocol, service) in &network.info.services {
                         let hostname = service.hostname.as_deref().unwrap_or(default_host);
                         if hostname.ends_with(&domain_name_suffix) || hostname == domain_name {
+                            // inbuxa: legacy-protocols LP-7. No TLS pin for a port
+                            // the switch has closed. Submission's port stays open
+                            // (the SMTP lock), so its record stays.
+                            if legacy_off
+                                && matches!(protocol, ServiceProtocol::Imap | ServiceProtocol::Pop3)
+                            {
+                                continue;
+                            }
                             let port = match protocol {
                                 ServiceProtocol::Imap => 993,
                                 ServiceProtocol::Pop3 => 995,
@@ -382,6 +417,12 @@ impl Server {
     }
 
     pub async fn get_pacc_for_domain(&self, domain_name: &str) -> trc::Result<String> {
+        // inbuxa: legacy-protocols LP-7
+        let pacc = if self.legacy_protocols_off().await? {
+            &self.core.network.info.pacc_jmap_only
+        } else {
+            &self.core.network.info.pacc
+        };
         self.get_directory_for_domain(domain_name)
             .await
             .caused_by(trc::location!())
@@ -390,15 +431,9 @@ impl Server {
                     .and_then(|directory| {
                         directory
                             .oidc_discovery_document()
-                            .map(|doc| self.core.network.info.pacc.build(&doc.url))
-                    })
-                    .unwrap_or_else(|| {
-                        self.core
-                            .network
-                            .info
-                            .pacc
-                            .build(&self.core.network.http.url_https)
+                            .map(|doc| pacc.build(&doc.url))
                     })
+                    .unwrap_or_else(|| pacc.build(&self.core.network.http.url_https))
             })
     }
 }

crates/common/src/network/legacy.rs

@@ -21,6 +21,10 @@
 //! a legacy protocol is refused before any password is looked at, so a
 //! listener that exists by mistake still lets nobody in.
 //!
+//! And nothing advertises what is closed (LP-7): client configuration and
+//! the suggested DNS records leave the legacy services out, or mark them as
+//! not offered, while the switch is off.
+//!
 //! Nothing here touches the host's firewall, NAT port-forwards or any proxy
 //! (LP-20). The server stops answering; what still routes the port is the
 //! operator's to reconcile.
@@ -31,6 +35,7 @@ use inbuxa_features::security::{
     listeners,
     protocol_policy::{self, ProtocolPolicy, SavedListener},
 };
+use registry::schema::enums::ServiceProtocol;
 use registry::types::{error::Error, id::ObjectId};
 use store::registry::bootstrap::Bootstrap;
 
@@ -302,6 +307,27 @@ impl Server {
     }
 }
 
+/// The services mail apps sign in to, which the switch turns off: nothing may
+/// offer them while it is (LP-7). SMTP here is submission -- mail apps
+/// sending -- since inbound mail is never a configured service.
+pub fn is_legacy_service(protocol: &ServiceProtocol) -> bool {
+    matches!(
+        protocol,
+        ServiceProtocol::Imap
+            | ServiceProtocol::Pop3
+            | ServiceProtocol::Smtp
+            | ServiceProtocol::Managesieve
+    )
+}
+
+impl Server {
+    /// Whether the server-wide switch is off, for the answers that must stop
+    /// offering legacy services (LP-7). Read per answer, as sign-in reads it.
+    pub async fn legacy_protocols_off(&self) -> trc::Result<bool> {
+        Ok(self.protocol_policy().await?.legacy_protocols.is_disabled())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -349,6 +375,26 @@ mod tests {
         assert_eq!(err.value_as_str(trc::Key::AccountName), None);
     }
 
+    #[test]
+    fn only_the_services_mail_apps_sign_in_to_are_legacy() {
+        for protocol in [
+            ServiceProtocol::Imap,
+            ServiceProtocol::Pop3,
+            ServiceProtocol::Smtp,
+            ServiceProtocol::Managesieve,
+        ] {
+            assert!(is_legacy_service(&protocol), "{protocol:?}");
+        }
+        for protocol in [
+            ServiceProtocol::Jmap,
+            ServiceProtocol::Caldav,
+            ServiceProtocol::Carddav,
+            ServiceProtocol::Webdav,
+        ] {
+            assert!(!is_legacy_service(&protocol), "{protocol:?}");
+        }
+    }
+
     #[test]
     fn the_domain_comes_from_the_name_given() {
         assert_eq!(domain_of(&basic("[email protected]")), Some("b.test".to_string()));

tests/e2e/legacy_protocols.py

@@ -17,7 +17,9 @@ submission -- locked open -- is refused with the spec's words, with the right
 password and with a wrong one, and refusals never add up to a disconnect
 (LP-11). And that a normal IMAP sign-in works with the switch on, before and
 after. And that while it is off, no listener the switch would close can be
-created, or made by an update (LP-4, test 4).
+created, or made by an update (LP-4, test 4), and nothing advertises what is
+closed: autoconfig, autodiscover and PACC offer no IMAP, POP3 or submission,
+and the suggested zone marks their SRV names not offered (LP-7, test 5).
 
 Passwords are generated into files under target/e2e and never printed.
 Everything is removed afterwards unless KEEP=1.
@@ -189,6 +191,40 @@ def smtp_auths(port, user, passwords):
     return replies
 
 
+def advertised(admin, admin_pw):
+    """What each client-configuration answer and the suggested zone offer."""
+    with urllib.request.urlopen(f"{HTTP}/mail/[email protected]",
+                                timeout=30) as resp:
+        autoconfig = resp.read().decode()
+    body = ('<?xml version="1.0" encoding="utf-8"?><Autodiscover xmlns="http://schemas.'
+            'microsoft.com/exchange/autodiscover/outlook/requestschema/2006"><Request>'
+            '<EMailAddress>[email protected]</EMailAddress><AcceptableResponseSchema>http://'
+            'schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a'
+            '</AcceptableResponseSchema></Request></Autodiscover>').encode()
+    req = urllib.request.Request(f"{HTTP}/autodiscover/autodiscover.xml", data=body, method="POST")
+    req.add_header("Content-Type", "text/xml")
+    with urllib.request.urlopen(req, timeout=30) as resp:
+        autodiscover = resp.read().decode()
+    with urllib.request.urlopen(f"{HTTP}/.well-known/user-agent-configuration.json",
+                                timeout=30) as resp:
+        pacc = json.load(resp).get("protocols", {})
+    got = one(admin, admin_pw, "x:Domain/get", {"ids": None, "properties": ["name", "dnsZoneFile"]})
+    zone = next((d.get("dnsZoneFile") or "" for d in got[1].get("list", [])
+                 if d.get("name") == "legacy.test"), "")
+    srv = {}
+    for line in zone.splitlines():
+        fields = line.split()
+        if "SRV" in fields and fields[0].startswith("_"):
+            srv[fields[0].split(".")[0] + "." + fields[0].split(".")[1]] = fields[-1]
+    return {
+        "autoconfig": {t for t in ("imap", "pop3", "smtp") if f'type="{t}"' in autoconfig},
+        "autodiscover": {t for t in ("IMAP", "POP3", "SMTP") if f"<Type>{t}</Type>" in autodiscover},
+        "pacc": {t for t in ("imap", "pop3", "smtp", "managesieve") if t in pacc},
+        "jmap": "jmap" in pacc,
+        "srv": srv,
+    }
+
+
 def settle(port, want, tries=30):
     """Wait for a port to reach the wanted state, so the check is not a race."""
     for _ in range(tries):
@@ -243,6 +279,15 @@ def main():
     check(accepts(PORTS["submissions"]), "submission accepts before the switch")
     check(accepts(PORTS["smtp"]), "inbound SMTP accepts before the switch")
 
+    # What is advertised with the switch on -- the control for LP-7.
+    before = advertised(admin, admin_pw)
+    print("     advertised before:", {k: sorted(v) if isinstance(v, set) else v
+                                      for k, v in before.items() if k != "srv"})
+    check(before["autoconfig"] and before["autodiscover"],
+          "autoconfig and autodiscover offer mail apps a server with the switch on")
+    check(before["srv"].get("_imaps._tcp", ".") != ".",
+          "the suggested zone offers IMAP with the switch on")
+
     # A normal sign-in works with the switch on -- the control for LP-6.
     check(imap_login(PORTS["imap"], admin, admin_pw).startswith("OK"),
           "IMAP sign-in works with the switch on")
@@ -295,6 +340,19 @@ def main():
     if not all(r == SMTP_REFUSAL for r in replies):
         print("     replies:", replies)
 
+    # Nothing advertises what is closed (LP-7, test 5).
+    during = advertised(admin, admin_pw)
+    check(not during["autoconfig"], "autoconfig offers no IMAP, POP3 or submission (LP-7)")
+    check(not during["autodiscover"], "autodiscover offers no IMAP, POP3 or submission (LP-7)")
+    check(not during["pacc"] and during["jmap"], "PACC offers JMAP and nothing legacy (LP-7)")
+    names = ("_imap._tcp", "_imaps._tcp", "_pop3._tcp", "_pop3s._tcp",
+             "_submission._tcp", "_submissions._tcp")
+    offered = {n: t for n, t in during["srv"].items() if n in names and t != "."}
+    check(not offered and "_imaps._tcp" in during["srv"],
+          "the suggested zone marks the legacy SRV names not offered, target . (LP-7)")
+    if offered or "_imaps._tcp" not in during["srv"]:
+        print("     srv:", during["srv"])
+
     # No listener the switch would close can be added while it is off (LP-4,
     # test 4), and the refusal names the policy.
     res = one(admin, admin_pw, "x:NetworkListener/set", {"create": {"m": {
@@ -341,6 +399,10 @@ def main():
     check(policy["legacyProtocols"] == "enabled", "switch reads back enabled")
     check(not policy["savedListeners"], "savedListeners is empty again (LP-5)")
 
+    after = advertised(admin, admin_pw)
+    check(after["autoconfig"] == before["autoconfig"] and after["srv"] == before["srv"],
+          "autoconfig and the suggested zone offer them again once back on")
+
     # And sign-in works again, with no restart.
     check(imap_login(PORTS["imap"], admin, admin_pw).startswith("OK"),
           "IMAP sign-in works again once the switch is back on")