Email Path – Where can my message get nuked?

Here’s a thread I had recently with a customer about why/how some of their emails weren’t getting to the intended recipient. Unfortunately, no matter what we did, the upstream email recipient’s (the receiver) system was rejecting the message – worse still it wasn’t even telling anyone it was rejecting it (oh thanks!) Anyways, I thought my email response to them here might help serve others who face similar problems – what the heck, it helps me reach my blog quota objective and maybe it will help someone too ;).


All the things we checked, to ensure the sending system was okay, were good, such as (check out for tools to help you validate those settings):


  • SenderID/SPF – for telling email systems we are delivering to, what IP addresses/systems are *allowed* to send email from a particular domain name (this is done as a TXT record in DNS)
  • PTR Record (Reverse DNS) – this is set with the ISP, to ensure that if an upstream mail server wants to make sure we are trustworthy, that when they look up the sending (our) mail servers IP, a valid hostname is returned (, etc.)


Unfortunately, the feedback we were getting is that people still aren’t getting emails. At this point, I think it is quite safe to say that the upstream mail recipient system (or antispam systems) are nuking the message. Frustrating as this is, the onus is now on them to figure out where things are going wrong. Below is the thread and suggestions but the reason for this post is to show some pretty Smart Art that helps illustrate the systems and places one should check *upstream* for blockages of email.




Yep, this looks 100% to be a problem on the other end of them terminating the emails as spam, etc. Avi has validated that you have a good senderID/SPF and PTR records (i.e. all the things that tell others your email is trustworthy have been checked).
Here’s the message Path. I believe that where the message is being stopped is one of the 4 “red” boxes and frankly, we can’t control any of them. I think you need to beg/plead with them to do more diligence on their end.


Sorry I can’t be of more help.




From: Avneet
Sent: Wednesday, October 20, 2010 4:39 PM
To: Steve
Cc: Sean Wallbridge
Subject: RE: Event

Hi Steve

I’ve exhausted all our avenues. Again, as you can see below, the Ambrosia server successfully handed over the email to Shaw. Where it went from there, only Shaw will know. Having said that, we should now probably speak with Shaw support and see if they can further track the emails, or shed some light on what’s going on. I will speak with them tomorrow morning.

Sean, in short, Steve has been sending emails to recipients at ‘’ and ‘’, and they have not been reaching their destinations (no NDR’s). However, if I track the message on the Ambrosia server, they are successfully handed over to ‘shawmail’ and/or ‘gmail’. I’ve also checked Ambrosia SPF records, SMTP diagnostics, blacklists, created a ‘Funky SMTP Connector’ and added the ‘’ and ‘’ domains (using ‘’ as the smart host), etc. Everything is ok regarding the Ambrosia messaging infrastructure. Any thoughts?




From: Steve
Sent: Wednesday, October 20, 2010 4:27 PM
To: Avneet
Subject: Event

Hi Avi,

This one definitely didn’t go through as I was right there with her last night and spoke to her this afternoon.

What do we need to do to figure this out, I really have no idea how many have not made it to their destination.