From 58212611bac6d342456853b7e044e9e947a2eecd Mon Sep 17 00:00:00 2001
From: Corbin <corbin@cbarts.net>
Date: Mon, 10 Jun 2024 14:37:41 -0400
Subject: [PATCH] Add default DKIM selector, note about dynamic selectors, TXT
 example

---
 README.md    | 28 +++++++++++++++++++++-------
 email_dns.py |  5 +++--
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 28fa4ed..3dc2293 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,8 @@
 # email_dns.py
 
-A simple Python script to resolve all email-related DNS records for a domain
+A Python script to resolve email-related DNS records for a domain.
 
-Example
+Example:
 
 ```
 $ python email_dns.py cbarts.net
@@ -18,18 +18,32 @@ $ python email_dns.py cbarts.net
                 "preference": "20"
             }
         ],
-        "spf": "v=spf1 include:_spf.protonmail.ch mx -all",
+        "spf": "v=spf1 a include:spf.protection.outlook.com -all",
         "dkim": [
             {
-                "type": "CNAME",
-                "value": "protonmail.domainkey.d54jb2xmwmmyjawzyztmko2lix3f4dz4uwu2rptmnailfrd6hqgeq.domains.proton.ch."
+                "application": "not specified",
+                "selector": "default",
+                "type": "TXT",
+                "value": "v=DKIM1; k=rsa; p=MIIBI...;"
             },
             {
+                "application": "exchange",
+                "selector": "selector1",
                 "type": "CNAME",
-                "value": "protonmail2.domainkey.d54jb2xmwmmyjawzyztmko2lix3f4dz4uwu2rptmnailfrd6hqgeq.domains.proton.ch."
+                "value": "selector1-contoso-com._domainkey.contoso.onmicrosoft.com."
+            },
+            {
+                "application": "exchange",
+                "selector": "selector2",
+                "type": "CNAME",
+                "value": "selector2-contoso-com._domainkey.contoso.onmicrosoft.com."
             }
         ],
-        "dmarc": "v=DMARC1; p=quarantine; rua=mailto:admin@cbarts.net,mailto:86be0037@mxtoolbox.dmarc-report.com; ruf=mailto:admin@cbarts.net,mailto:86be0037@forensics.dmarc-report.com"
+        "dmarc": "v=DMARC1; p=quarantine; adkim=s; aspf=s; fo=1; ri=3600;"
     }
 }
 ```
+
+## Limitations
+
+Applications with *dynamic* selector names will not be detected, e.g. smtp2go (`s12345._domainkey.<domain>`)
\ No newline at end of file
diff --git a/email_dns.py b/email_dns.py
index 21ed058..fcb1125 100755
--- a/email_dns.py
+++ b/email_dns.py
@@ -6,8 +6,9 @@ import re
 import json
 
 dkim_selectors = { # <selector>._domainkey.<domain>
-    'none': [
-        'dkim'
+    # Applications with dynamic selector names will not be detected, e.g. smtp2go (s12345._domainkey.<domain>)
+    'not specified': [
+        'dkim', 'default'
     ],
     'google': [
         'google'