MX record and TCP port checks added

templates/healthchecks.html

@@ -1,5 +1,35 @@
 {{ define "content" }}
 <div>
+    <h3>TCP ports</h3>
+    <p>
+    {{ if eq "" .FailingPorts }}
+        All the required ports are open &#x2714;
+    {{ else }}
+        Some ports are not open &#x2717;
+        check your firewall for ports {{ .FailingPorts }}
+    {{ end }}
+    </p>
+    <h3>DNS records</h3>
+    <h4>MX</h4>
+    <p>
+        {{ if eq .MxRecordShouldBe .MxRecordIs }}
+        Your MX record is OK &#x2714;
+        {{ else }}
+        Your MX record is wrong &#x2717;<br/>
+        It should be:
+    <form class="pure-form pure-form-aligned">
+        <div class="pure-control-group">
+            <label for="mx-host">Host</label>
+            <input id="mx-host" class="copyable" readonly type="text" value="@"/>
+        </div>
+
+        <div class="pure-control-group">
+            <label for="mx-value">Value</label>
+            <input id="mx-value" class="copyable" readonly type="text" value="{{.MxRecordShouldBe}}"/>
+        </div>
+    </form>
+    {{ end }}
+    </p>
     <h4>DKIM</h4>
     <p>
         {{ if eq .DkimRecordShouldBe .DkimRecordIs }}

web/healthchecks.go

@@ -1,6 +1,7 @@
 package web
 
 import (
+	"fmt"
 	"henrymail/config"
 	"henrymail/dkim"
 	"henrymail/models"
@@ -26,19 +27,27 @@ func (wa *wa) healthChecks(w http.ResponseWriter, r *http.Request, u *models.Use
 		return
 	}
 	dkimActual := fetchDkimActual()
+	mxActual := fetchMxActual()
+	mxExpected := config.GetString(config.ServerName) + "." // MX records expect a trailing dot
 
 	data := struct {
 		layoutData
 		DkimRecordIs       string
 		DkimRecordShouldBe string
 		SpfRecordIs        string
 		SpfRecordShouldBe  string
+		MxRecordIs         string
+		MxRecordShouldBe   string
+		FailingPorts       string
 	}{
 		layoutData:         *ld,
 		DkimRecordIs:       dkimActual,
 		DkimRecordShouldBe: dkimExpected,
 		SpfRecordIs:        spfActual,
 		SpfRecordShouldBe:  spfExpected,
+		MxRecordIs:         mxActual,
+		MxRecordShouldBe:   mxExpected,
+		FailingPorts:       fetchFailingPorts(),
 	}
 	wa.healthChecksView.render(w, data)
 }
@@ -69,3 +78,41 @@ func fetchSpfActual() string {
 	}
 	return spfActual
 }
+
+func fetchMxActual() string {
+	mxActual := ""
+	mxes, e := net.LookupMX(config.GetString(config.Domain))
+	if e != nil {
+		mxActual = e.Error()
+	} else {
+		mxesLen := len(mxes)
+		if mxesLen != 1 {
+			// Should be just 1 MX record
+			mxActual = fmt.Sprintf("Expecting exactly 1 mx record, found %d", mxesLen)
+		} else {
+			// MX record should be referring to this server
+			mxActual = mxes[0].Host
+		}
+	}
+	return mxActual
+}
+
+func fetchFailingPorts() string {
+	// Should be able to open a socket on these ports, to ourselves
+	portsTest := []string{
+		"25",
+		"143",
+		"443",
+		"587",
+	}
+	var failedPorts []string
+	for _, port := range portsTest {
+		con, e := net.Dial("tcp", config.GetString(config.ServerName)+":"+port)
+		if e != nil {
+			failedPorts = append(failedPorts, port)
+		} else {
+			_ = con.Close()
+		}
+	}
+	return strings.Join(failedPorts, ",")
+}