1package spf_test

2

3import (

4 "context"

5 "log"

6 "log/slog"

7 "net"

8

9 "github.com/mjl-/mox/dns"

10 "github.com/mjl-/mox/smtp"

11 "github.com/mjl-/mox/spf"

12)

13

14func ExampleVerify() {

15 ctx := context.Background()

16 resolver := dns.StrictResolver{}

17

18 args := spf.Args{

19 // IP from SMTP session.

20 RemoteIP: net.ParseIP("1.2.3.4"),

21

22 // Based on "MAIL FROM" in SMTP session.

23 MailFromLocalpart: smtp.Localpart("user"),

24 MailFromDomain: dns.Domain{ASCII: "sendingdomain.example.com"},

25

26 // From HELO/EHLO in SMTP session.

27 HelloDomain: dns.IPDomain{Domain: dns.Domain{ASCII: "mx.example.com"}},

28

29 // LocalIP and LocalHostname should be set, they may be used when evaluating macro's.

30 }

31

32 // Lookup SPF record and evaluate against IP and domain in args.

33 received, domain, explanation, authentic, err := spf.Verify(ctx, slog.Default(), resolver, args)

34

35 // received.Result is always set, regardless of err.

36 switch received.Result {

37 case spf.StatusNone:

38 log.Printf("no useful spf result, domain probably has no spf record")

39 case spf.StatusNeutral:

40 log.Printf("spf has no statement on ip, with \"?\" qualifier")

41 case spf.StatusPass:

42 log.Printf("ip is authorized")

43 case spf.StatusFail:

44 log.Printf("ip is not authorized, with \"-\" qualifier")

45 case spf.StatusSoftfail:

46 log.Printf("ip is probably not authorized, with \"~\" qualifier, softfail")

47 case spf.StatusTemperror:

48 log.Printf("temporary error, possibly dns lookup failure, try again soon")

49 case spf.StatusPermerror:

50 log.Printf("permanent error, possibly invalid spf records, later attempts likely have the same result")

51 }

52 if err != nil {

53 log.Printf("error: %v", err)

54 }

55 if explanation != "" {

56 log.Printf("explanation from remote about spf result: %s", explanation)

57 }

58 log.Printf("result is for domain %s", domain) // mailfrom or ehlo/ehlo.

59 log.Printf("dns lookups dnssec-protected: %v", authentic)

60}

61