Fix MX and SPF check

- take into account priority in MX check
- use EMAIL_DOMAIN in SPF instead of MX server

app/config.py

@@ -49,7 +49,6 @@ POSTFIX_SERVER = os.environ.get("POSTFIX_SERVER", "1.1.1.1")
 EMAIL_SERVERS_WITH_PRIORITY = eval(
     os.environ["EMAIL_SERVERS_WITH_PRIORITY"]
 )  # [(10, "email.hostname.")]
-EMAIL_SERVERS = [es for _, es in EMAIL_SERVERS_WITH_PRIORITY]
 
 # these emails are ignored when computing stats
 if os.environ.get("IGNORED_EMAILS"):

app/dashboard/templates/dashboard/domain_detail/dns.html

@@ -27,7 +27,9 @@
         {% endif %}
       </div>
 
-      <div class="mb-2">Add the following MX DNS record to your domain</div>
+      <div class="mb-2">Add the following MX DNS record to your domain.
+        Please note that there's a point (<em>.</em>) at the end of target addresses.
+      </div>
 
       {% for priority, email_server in EMAIL_SERVERS_WITH_PRIORITY %}
         <div class="mb-3 p-3" style="background-color: #eee">

app/dashboard/views/domain_detail.py

@@ -1,7 +1,7 @@
 from flask import render_template, request, redirect, url_for, flash
 from flask_login import login_required, current_user
 
-from app.config import EMAIL_SERVERS_WITH_PRIORITY, EMAIL_SERVERS, DKIM_DNS_VALUE
+from app.config import EMAIL_SERVERS_WITH_PRIORITY, DKIM_DNS_VALUE, EMAIL_DOMAIN
 from app.dashboard.base import dashboard_bp
 from app.dns_utils import (
     get_mx_domains,
@@ -33,9 +33,12 @@ def domain_detail_dns(custom_domain_id):
         if request.form.get("form-name") == "check-mx":
             mx_domains = get_mx_domains(custom_domain.domain)
 
-            if mx_domains != EMAIL_SERVERS:
+            if sorted(mx_domains) != sorted(EMAIL_SERVERS_WITH_PRIORITY):
                 mx_ok = False
-                mx_errors = get_mx_domains(custom_domain.domain, keep_priority=True)
+                # build mx_errors to show to user
+                mx_errors = [
+                    f"{priority} {domain}" for (priority, domain) in mx_domains
+                ]
             else:
                 flash(
                     "Your domain is verified. Now it can be used to create custom alias",
@@ -50,15 +53,7 @@ def domain_detail_dns(custom_domain_id):
                 )
         elif request.form.get("form-name") == "check-spf":
             spf_domains = get_spf_domain(custom_domain.domain)
-            for email_server in EMAIL_SERVERS:
-                email_server = email_server[:-1]  # remove the trailing .
-                if email_server not in spf_domains:
-                    flash(
-                        f"{email_server} is not included in your SPF record.", "warning"
-                    )
-                    spf_ok = False
-
-            if spf_ok:
+            if EMAIL_DOMAIN in spf_domains:
                 custom_domain.spf_verified = True
                 db.session.commit()
                 flash("The SPF is setup correctly", "success")
@@ -68,6 +63,8 @@ def domain_detail_dns(custom_domain_id):
                     )
                 )
             else:
+                flash(f"{EMAIL_DOMAIN} is not included in your SPF record.", "warning")
+                spf_ok = False
                 spf_errors = get_txt_record(custom_domain.domain)
 
         elif request.form.get("form-name") == "check-dkim":
@@ -87,11 +84,7 @@ def domain_detail_dns(custom_domain_id):
                 dkim_ok = False
                 dkim_errors = get_txt_record(f"dkim._domainkey.{custom_domain.domain}")
 
-    spf_include_records = []
-    for priority, email_server in EMAIL_SERVERS_WITH_PRIORITY:
-        spf_include_records.append(f"include:{email_server[:-1]}")
-
-    spf_record = f"v=spf1 {' '.join(spf_include_records)} -all"
+    spf_record = f"v=spf1 include:{EMAIL_DOMAIN} -all"
 
     dkim_record = f"v=DKIM1; k=rsa; p={DKIM_DNS_VALUE}"
 

app/dns_utils.py

@@ -1,8 +1,9 @@
 import dns.resolver
 
 
-def get_mx_domains(hostname, keep_priority=False) -> [str]:
-    """return list of (domain name). priority is also included if `keep_priority`
+def get_mx_domains(hostname) -> [(int, str)]:
+    """return list of (priority, domain name).
+    domain name ends with a "." at the end.
     """
     try:
         answers = dns.resolver.query(hostname, "MX")
@@ -13,10 +14,9 @@ def get_mx_domains(hostname, keep_priority=False) -> [str]:
 
     for a in answers:
         record = a.to_text()  # for ex '20 alt2.aspmx.l.google.com.'
-        if not keep_priority:
-            record = record.split(" ")[1]  # alt2.aspmx.l.google.com.
+        parts = record.split(" ")
 
-        ret.append(record)
+        ret.append((int(parts[0]), parts[1]))
 
     return ret