Web Management

Some, frustrated that some of their emails are not coming in due to 'Sender Verify' checks, wonder if it's worth it.

Let's face it. Email is important to all of us. We need to ensure that we get all of our important messages. But, we also don't want to wade through hundreds of junk mails, do we? Finding a balance is difficult, and trying to filter out spam is a multi-part process, each with it's pros and cons. Is Sender Verify/Callout worth the trouble?

Spam Volume and Slowing The Flow

Below is a log file, just scanned for rejected mail. These are emails that were not accepted for delivery because the sender's server could not verify the sender address. The server simply looks at who the message says is the sender, and who to reply back to in case there is a problem delivering. If our server doesn't get verification that the alleged sender will accept email, our server doesn't accept theirs.

Let's assume that we did accept that email without checking first. It comes in, and the recipients mailbox is full. We want to send a notice back to the sender saying it can't be delivered... but now we can't because original sender doesn't exist. So, we get stuck with email with nowhere to go.  How much?

This log file is for just 4 minutes. FOUR minutes.

  1. 2007-12-17 17:56:06 H=(pc3) [190.136.2.77] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from bossmtp01.bcbsma.com [216.118.190.19] was: 550 #5.1.0 Address rejected.
  2. 2007-12-17 17:56:09 H=([76.164.23.253]) [76.164.23.253] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx2.mail.hostpoint.ch [217.26.49.139] was: 550 no such address here
  3. 2007-12-17 17:56:11 H=(sprint.ca) [82.150.166.12] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mailin.planet.nl [195.121.6.51] was: 550 5.1.1 User unknown
  4. 2007-12-17 17:56:11 H=(18913196051.user.veloxzone.com.br) [189.13.196.51] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx1.biz.mail.yahoo.com [4.79.181.18] was: 550 relaying denied for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  5. 2007-12-17 17:56:11 H=(usuario-d61b670.sinfo.net) [200.46.5.31] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from blueplateevents.com.s5a1.psmtp.com [64.18.4.10] was: 550 No such user - psmtp
  6. 2007-12-17 17:56:18 H=(mediaone.net) [218.201.74.50] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx.tm.net.my [202.188.0.213] was: 550 5.1.1 <This email address is being protected from spambots. You need JavaScript enabled to view it.> recipient rejected
  7. 2007-12-17 17:56:19 H=(18913196051.user.veloxzone.com.br) [189.13.196.51] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from EMAIL.SILVERPEAKSYSTEMS.COM [128.242.109.232] was: 550 5.7.1 Unable to relay for This email address is being protected from spambots. You need JavaScript enabled to view it.
  8. 2007-12-17 17:56:24 H=(BD46A86.fln.virtua.com.br) [189.4.106.134] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from norika-fujiwara-com.mr.outblaze.com [64.62.181.91] was: 550 <This email address is being protected from spambots. You need JavaScript enabled to view it.>: User unknown
  9. 2007-12-17 17:56:24 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from kwikkopy1004.com [70.87.77.2] was: 550 No Such User Here
  10. 2007-12-17 17:56:24 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  11. 2007-12-17 17:56:24 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  12. 2007-12-17 17:56:26 H=([200.11.68.131]) [200.11.68.131] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from MAIL.american-box.com [63.83.159.194] was: 550 5.1.1 User unknown
  13. 2007-12-17 17:56:27 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mxvm3.mail.yahoo.com [67.28.113.14] was: 550 relaying denied for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  14. 2007-12-17 17:56:27 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  15. 2007-12-17 17:56:27 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  16. 2007-12-17 17:56:30 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from smtp.where.secureserver.net [64.202.166.12] was: 553 sorry, relaying denied from your location [67.15.4.42] (#5.7.1)
  17. 2007-12-17 17:56:30 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  18. 2007-12-17 17:56:30 H=(nombre-2079371e) [190.82.223.158] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  19. 2007-12-17 17:56:41 H=(tm.net.my) [69.50.70.248] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx.videotron.ca [24.201.245.37] was: 550 5.1.1 unknown or illegal alias: This email address is being protected from spambots. You need JavaScript enabled to view it.
  20. 2007-12-17 17:56:52 H=(orgnameu0ipq4k) [84.228.102.237] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from stretchinc.com [207.135.74.34] was: 550 5.1.1 <This email address is being protected from spambots. You need JavaScript enabled to view it.>... User unknown
  21. 2007-12-17 17:56:57 H=(hvwrr.cheapnet.it) [80.67.119.145] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from casselsbrock.com.mail5.psmtp.com [64.18.5.10] was: 550 No such user - psmtp
  22. 2007-12-17 17:57:02 H=(windowsd3858ec.cantv.net) [190.73.125.191] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from facs.org.MAIL5.PSMTP.com [64.18.5.10] was: 550 No such user - psmtp
  23. 2007-12-17 17:57:02 H=(windowsd3858ec.cantv.net) [190.73.125.191] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  24. 2007-12-17 17:57:17 H=(dsl-189-132-147-126.prod-infinitum.com.mx) [189.132.147.126] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from INBOUND.JBNL.NET.NETSOLMAIL.net [205.178.149.7] was: 550 5.2.1 <This email address is being protected from spambots. You need JavaScript enabled to view it.>... Mailbox disabled for this recipient
  25. 2007-12-17 17:57:26 H=(p6eeb1e.osakac00.ap.so-net.ne.jp) [218.110.235.30] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx2.supremebox.com [209.25.170.16] was: 550 relay not permitted
  26. 2007-12-17 17:57:28 H=(p6eeb1e.osakac00.ap.so-net.ne.jp) [218.110.235.30] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from nutrazu.com.mail9.psmtp.com [64.18.6.14] was: 550 5.7.1 Unable to relay for This email address is being protected from spambots. You need JavaScript enabled to view it.
  27. 2007-12-17 17:57:29 H=(pool-70-18-200-72.ny325.east.verizon.net) [70.18.200.72] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mail.reinesdesign.com [207.58.140.57] was: 550 sorry, no mailbox here by that name. (#5.7.17)
  28. 2007-12-17 17:57:30 H=(p6eeb1e.osakac00.ap.so-net.ne.jp) [218.110.235.30] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from smtp.where.secureserver.net [64.202.166.12] was: 553 sorry, relaying denied from your location [67.15.4.42] (#5.7.1)
  29. 2007-12-17 17:57:31 H=(soporte.cicorporativo) [189.141.12.81] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx.vasoftware.com [208.48.95.23] was: 550 unrouteable address
  30. 2007-12-17 17:57:31 H=(your-8e56f55ee8) [81.97.138.52] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from smtp.where.secureserver.net [64.202.166.12] was: 553 sorry, relaying denied from your location [67.15.4.42] (#5.7.1)
  31. 2007-12-17 17:57:33 H=(your-8e56f55ee8) [81.97.138.52] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from sm06.internetmailserver.net [64.79.170.136] was: 550 <This email address is being protected from spambots. You need JavaScript enabled to view it.> No such user here
  32. 2007-12-17 17:57:38 H=(your-8e56f55ee8) [81.97.138.52] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mail1.netscalibur.it [194.244.215.2] was: 550 RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.> User unknown
  33. 2007-12-17 17:57:43 H=(nata3eb5fe520a) [62.117.181.236] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from AMETSOC.ORG.S8A1.PSMTP.COM [64.18.7.10] was: 550 unknown user <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  34. 2007-12-17 17:57:51 H=(your-8e56f55ee8) [81.97.138.52] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from ASPMX.L.GOOGLE.com [64.233.163.27] was: 550 5.1.1 No such user 15si1739643nzp
  35. 2007-12-17 17:58:10 H=(220-253-42-23.VIC.netspace.net.au) [220.253.42.23] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from dpmail23.doteasy.com [65.61.209.23] was: 550 <This email address is being protected from spambots. You need JavaScript enabled to view it.> No such user here
  36. 2007-12-17 17:58:30 H=(189-46-18-20.dsl.telesp.net.br) [189.46.18.20] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mail.kasa-chorych.silesia.pl [83.238.17.75] was: 550 5.7.1 Requested action not taken: mailbox not available
  37. 2007-12-17 17:58:33 H=(your5653e30a79.myhome.westell.com) [71.173.86.85] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mail.pacificnet.net [216.152.194.119] was: 551 Command RCPT User not local and relaying not permitted from you (67.15.4.42)
  38. 2007-12-17 17:58:33 H=(your5653e30a79.myhome.westell.com) [71.173.86.85] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  39. 2007-12-17 17:58:33 H=(your5653e30a79.myhome.westell.com) [71.173.86.85] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  40. 2007-12-17 17:58:34 H=(your5653e30a79.myhome.westell.com) [71.173.86.85] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  41. 2007-12-17 17:58:36 H=(189-46-18-20.dsl.telesp.net.br) [189.46.18.20] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mail.hhcorp.org [209.43.5.80] was: 550 #5.1.0 Address rejected.
  42. 2007-12-17 17:58:44 H=(189-46-18-20.dsl.telesp.net.br) [189.46.18.20] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from guardian.sph.harvard.edu [134.174.190.3] was: 550 No such user (This email address is being protected from spambots. You need JavaScript enabled to view it.)
  43. 2007-12-17 17:58:54 H=(equipo1) [190.1.207.40] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx1.balanced.swarthy.mail.dreamhost.com [208.113.200.31] was: 550 <This email address is being protected from spambots. You need JavaScript enabled to view it.>: Recipient address rejected: User unknown in virtual alias table
  44. 2007-12-17 17:59:03 H=(ciber06) [201.223.179.18] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from ingwaz.pair.com [209.68.1.186] was: 554 <This email address is being protected from spambots. You need JavaScript enabled to view it.>: Recipient address rejected: Sorry, no mailbox here by that name (#5.1.1)
  45. 2007-12-17 17:59:07 H=(usuario) [62.42.53.59] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mail-incoming.gate.com [64.71.41.19] was: 554 Hi [67.15.4.42], unresolvable address: <This email address is being protected from spambots. You need JavaScript enabled to view it.>
  46. 2007-12-17 17:59:14 H=(wanadoo.fr) [222.197.188.37] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mx.tm.net.my [202.188.0.213] was: 550 5.1.1 <This email address is being protected from spambots. You need JavaScript enabled to view it.> recipient rejected
  47. 2007-12-17 17:59:51 H=(pvw3ke65xf4wog) [81.13.152.24] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>: response to "RCPT TO:<This email address is being protected from spambots. You need JavaScript enabled to view it.>" from mr1.iworld.com [63.236.72.185] was: 550 5.2.1 <This email address is being protected from spambots. You need JavaScript enabled to view it.>... Mailbox disabled for this recipient
  48. 2007-12-17 17:59:56 H=(189-46-18-20.dsl.telesp.net.br) [189.46.18.20] sender verify fail for <This email address is being protected from spambots. You need JavaScript enabled to view it.>

4 minutes, 48 emails blocked. And this is just the mail not accepted and not scanned for content. There are hundreds that get accepted and then get blocked by content/spam filters.

So, should a server accept all of that mail, and deliver it to the recipients? Would you want those 12 emails a minute coming into your mailbox? This was just a random sampling taken as I wrote this. It may be more or less throughout the day, but you should be able to see that there is a lot of unwanted email being blocked with this simple test.  Now, when your mail doesn't get through because of a sender verify issue, ask not why this server is blocking you, but why your server is not verifying you.

Sender Verify... Worth it.