Solved

SMTP Mail Issue

Posted on 2011-03-04
3
1,198 Views
Last Modified: 2012-05-11
I have an automated system that generates PDF invoices and sends them to my customers on a regular basis. They are not receiving these e-mails.

I am using PHP on a Windows server to send these PDF as mime attachments using SMTP. We were using our ISP's SMTP, but now we are trying SMTP2Go corporate. We send the emails in batches of 250.

When I send these emails to myself, I get them on my company e-mail, my yahoo email, and my gmail. About 80% of these are getting delivered (out of about 220) daily. When we resend, they typically get delivered, about 99% of the time.

I am not getting any error messages our bounceback, I am not blacklisted, and we can send mail to these recipients. I used several tools to check my SPF and DNS settings and everything looks fine, I used the Port25 testing utilities and getting this:

SPF check:          neutral
DomainKeys check:   neutral
DKIM check:         pass
Sender-ID check:    neutral
SpamAssassin check: ham

I have many customers who have never had a receipt issue. I am also having the same issue whether I use my ISP (Comcast) or SMTP2Go's SMTP service - both require authentication and I tried multiple ports with both.

The server sending e-mail is an internal server that uses SMTP, it is not on the web.

E-mail is sending properly, it's just not being received.

The e-mails have a 3 sentance body, a subject, and a PDF attached and come from an actual sender e-mail.

I am at my wit's end; any suggestions would be greatly appreciated.

==========================================================
Details:
==========================================================

HELO hostname:  smtpcorp.com
Source IP:      174.143.60.32
mail-from:      yyyy@xxxx.com

----------------------------------------------------------
SPF check details:
----------------------------------------------------------
Result:         neutral (SPF-Result: None)
ID(s) verified: smtp.mail=yyyy@xxxx.com
DNS record(s):
    xxxx.com. SPF (no records)
    xxxx.com. 1200 IN TXT "i=240&m=domains-mx2-p12"

----------------------------------------------------------
DomainKeys check details:
----------------------------------------------------------
Result:         neutral (message not signed)
ID(s) verified: header.From=yyyy@xxxx.com
DNS record(s):

----------------------------------------------------------
DKIM check details:
----------------------------------------------------------
Result:         pass (signature verifies; identity doesn't match any
headers)
ID(s) verified: header.d=smtpcorp.com
0
Comment
Question by:Candidochris
3 Comments
 
LVL 10

Assisted Solution

by:NetExpert-Warszawa
NetExpert-Warszawa earned 100 total points
ID: 35038538
Are you able to look into your mail server logs? Probably not yourself, but could you ask some ISP's or SMTP2Go's support?  You need to know the response from a customers mail server.
0
 
LVL 6

Accepted Solution

by:
DewFreak earned 400 total points
ID: 35038601
Add a SPF record - some systems will not accept without it so neutral is no good
Ensure your mail server IP is reversed

You are having to bend to ever filter out in the world that your customers use so at times this can be difficult.  You may need your clients to manually add you to allowed filters etc.

I would NOT use your ISP's mail server since it can become blacklisted at anytime, you have no control etc.  Not sure of this third party SMTP service.

Spend $15 a month and get your own mail server so you can tweak and control all aspects of it.

There are a lot of points of failure that can be happening here and you not being able to control the mail server or look at logs is an issue.
0
 

Author Comment

by:Candidochris
ID: 35039844
NetExpert-Warszawa:Are you able to look into your mail server logs? Probably not yourself, but could you ask some ISP's or SMTP2Go's support?  You need to know the response from a customers mail server.
I have them looking at the logs, but I can't do it myself.

Add a SPF record - some systems will not accept without it so neutral is no good
Ensure your mail server IP is reversed

You are having to bend to ever filter out in the world that your customers use so at times this can be difficult.  You may need your clients to manually add you to allowed filters etc.

I have been actively working on this.

I would NOT use your ISP's mail server since it can become blacklisted at anytime, you have no control etc.  
I am not anymore.

Not sure of this third party SMTP service.
We started using them because they appear to have things covered pretty well.
http://corporate.smtp2go.com/howitworks/email-deliverability.php
 

Spend $15 a month and get your own mail server so you can tweak and control all aspects of it.
Any suggestions on where to do this for $15?

There are a lot of points of failure that can be happening here and you not being able to control the mail server or look at logs is an issue.

Agreed - thanks for the assistance.
0

Featured Post

Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article is essential to make secure Yahoo Mail connection without facing any issue. It is providing simple steps to configure your Yahoo Mailbox to Hard drive using Microsoft Outlook.
This article covers general Notes 8.5 troubleshooting information including recreating the Notes\Data folder.
This video shows how to remove a single email address from the Outlook 2010 Auto Suggestion memory. NOTE: For Outlook 2016 and 2013 perform the exact same steps. Open a new email: Click the New email button in Outlook. Start typing the address: …
Many of my clients call in with monstrous Gmail overloading issues with Outlook. A quick tip is to turn off the All Mail and Important folders from synching. Here is a quick video I made to show you how to turn off these and other folders in Gmail s…

867 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now