Email: Beyond the send button

A guide to what happens after you hit the send button on an email

Transcript

1. Email Beyond the send button
2. Saying Hello 220 mail.example.com SMTP\n
3. Saying Hello 220 mail.example.com SMTP\n EHLO bob.example.com\n
4. Saying Hello 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n
5. Is this line secure? 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n
6. Is this line secure? 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n
7. Is this line secure? 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ]
8. Lets start over… 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n
9. Lets start over… 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n
10. Papers please 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n AUTH LOGIN\n
11. Papers please 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n AUTH LOGIN\n 334 VXNlcm5hbWU6\n
12. Papers please 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n AUTH LOGIN\n 334 VXNlcm5hbWU6\n Ym9iQGV4YW1wbGUuY29t\n
13. Papers please 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n AUTH LOGIN\n 334 VXNlcm5hbWU6\n Ym9iQGV4YW1wbGUuY29t\n 334 UGFzc3dvcmQ6\n
14. Papers please 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n AUTH LOGIN\n 334 VXNlcm5hbWU6\n Ym9iQGV4YW1wbGUuY29t\n 334 UGFzc3dvcmQ6\n cGFzc3dvcmQ=\n
15. Papers please 220 mail.example.com SMTP\n EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250-AUTH PLAIN LOGIN\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO bob.example.com\n 250-mail.example.com here, nice to meet you bob.example.com\n 250 AUTH PLAIN LOGIN\n AUTH LOGIN\n 334 VXNlcm5hbWU6\n Ym9iQGV4YW1wbGUuY29t\n 334 UGFzc3dvcmQ6\n cGFzc3dvcmQ=\n 235 Authentication succeeded\n
16. Sending a message MAIL FROM: bob@example.com\n
17. Sending a message MAIL FROM: bob@example.com\n 250 ok\n
18. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n
19. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n
20. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n
21. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n
22. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n \n
23. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n \n What up dan? I’m just keeping it bob.\n - Bob\n
24. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n
25. Sending a message MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n 250 message queued\n
26. Bye Bye MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n 250 message queued\n QUIT\n
27. Bye Bye MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n 250 message queued\n QUIT\n 221 goodbye!\n
28. And then…
29. MX Records $ dig MX danielknell.co.uk danielknell.co.uk. 3571 IN MX 1 aspmx.l.google.com. danielknell.co.uk. 3571 IN MX 5 alt1.aspmx.l.google.com. danielknell.co.uk. 3571 IN MX 5 alt2.aspmx.l.google.com. danielknell.co.uk. 3571 IN MX 10 alt3.aspmx.l.google.com. danielknell.co.uk. 3571 IN MX 10 alt4.aspmx.l.google.com.
30. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n
31. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n
32. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n 250-mx.google.com at your service, mail.example.com\n 250 STARTTLS\n
33. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n 250-mx.google.com at your service, mail.example.com\n 250 STARTTLS\n STARTTLS\n
34. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n 250-mx.google.com at your service, mail.example.com\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n
35. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n 250-mx.google.com at your service, mail.example.com\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ]
36. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n 250-mx.google.com at your service, mail.example.com\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO mail.example.com\n
37. Passing it on 220 mx.google.com ESMTP i2si23053074wja.89 - gsmtp\n EHLO mail.example.com\n 250-mx.google.com at your service, mail.example.com\n 250 STARTTLS\n STARTTLS\n 220 Go ahead\n [ magical encryption stuff ] EHLO mail.example.com\n 250 -mx.google.com at your service, mail.example.com\n
38. Message MAIL FROM: bob@example.com\n
39. SPF Record $ dig TXT example.com example.com. 3585 IN TXT "v=spf1 ip4:203.0.113.0/24 ~all”
40. Passing it on MAIL FROM: bob@example.com\n 250 ok\n
41. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n
42. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n
43. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n
44. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n
45. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com To: contact@danielknell.co.uk DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=example; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n
46. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com\n To: contact@danielknell.co.uk\n DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=foobar; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n
47. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com\n To: contact@danielknell.co.uk\n DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=foobar; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n What up dan? I’m just keeping it bob.\n - Bob\n
48. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com\n To: contact@danielknell.co.uk\n DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=foobar; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n
49. DKIM Recod $ dig TXT foobar._domainkey.example.com foobar._domainkey.example.com. 2607 IN TXT "v=DKIM1\; k=rsa\; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCXBN08ApG6sfTDR0CQlmQ2aSEaaHnyux7HAv3AmKeKkUycvy1 SiT2bM6HJqozV+MkEi4Ut+tHm0OkTx4d4DyX7rT0pI6nJ6R75calBpT+h/ pTC1TWrY8C0CIxutlwBKgeJxbJmXVvW/g9PdaLMREITMizTOS3dXxoOJdWj/SRjwwIDAQAB"
50. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com\n To: contact@danielknell.co.uk\n DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=foobar; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n 250 message queued\n
51. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com\n To: contact@danielknell.co.uk\n DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=foobar; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n 250 message queued\n QUIT\n
52. Passing it on MAIL FROM: bob@example.com\n 250 ok\n RCPT TO: contact@danielknell.co.uk\n 250 ok\n DATA\n 354 Start mail input; end with <CRLF>.<CRLF>\n Subject: Bobbing it up\n From: bob@example.com\n To: contact@danielknell.co.uk\n DKIM-Signature a=rsa-sha1; q=dns; d=example.com; i=bob@example.com; s=foobar; c=relaxed/ simple; t=1117574938; x=1118006938; h=from:to:subject:date; b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSbav+yuU4zGeeruD00lszZVoG4ZHRNiYzR\n \n What up dan? I’m just keeping it bob.\n - Bob\n .\n 250 message queued\n QUIT\n 221 goodbye!\n
53. Bonus material
54. DMARC $ dig TXT _dmarc.example.com _dmarc.example.com. 57 IN TXT "v=DMARC1; p=none; rua=mailto:postmaster@example.com; ruf=mailto:postmaster@example.com;"
55. Useful terms • SMTP (Simple Mail Transfer Protocol) • SPF (Sender Policy Framework) • DKIM (Domain Keys Identified Mail) • DMARC (Domain-based Message Authentication, Reporting & Conformance)
56. Thats all folks email: contact@danielknell.co.uk twitter: @danielknell website: http://danielknell.co.uk/