Unable to send email to Smart Packaging Solutions

You were sent to this webpage because you are unable to send emails to Smart Packaging Solutions (SPS). Our server does a couple of simple checks whenever a distant server tries to send emails. These checks currently block around five thousand spam emails per day.

To solve this issue, your IT department will have to solve some misconfigurations. Let's assume the following hypotheses are valid.


  • you are using your corporate email server.
  • you are able to send and recieve emails to and from most domains.
  • your email server is not listed as a spam source on a major RBL.

First check: Forward Confirmed reverse DNS (FCrDNS)

The FCrDNS validates the distant server IP address configuration against the RFC 1912 (Common DNS Operational and Configuration Errors, february 1996).

Every Internet-reachable host should have a name. The consequences of this are becoming more and more obvious. Many services available on the Internet will not talk to you if you aren't correctly registered in the DNS.

Make sure your PTR and A records match. For every IP address, there should be a matching PTR record in the in-addr.arpa domain.  If a host is multi-homed, (more than one IP address) make sure that all IP addresses have a corresponding PTR record (not just the first one). Failure to have matching PTR and A records can cause loss of Internet services similar to not being registered in the DNS at all.  Also, PTR records must point back to a valid A record, not a alias defined by a CNAME."

 You can check your outgoing mail server IP address on multirbl.valli.org. Visit the webpage, enter the IP address of the server you want to test and press send. You want to see the following:

  1. a valid rDNS for the server IP address.
  2. a valid IP address for the server name returned by the first step.
  3. matching IP addresses for step 1 and 2.

Results of the FCrDNS test on the SPS email server IP address:


If your server IP address is not FCrDNS, the SPS server will be terminate the connection with an error message: "cannot find your hostname".

Second check: FQDN HELO command

 When a mailserver establish a connection, it introduce himself with the HELO command. For example: "HELO mail.company.com". The server name given with the HELO command must be a Fully Qualified Domain Name (FQDN). Which means that the name is valid and reachable on the internet.

The issue of invalid HELO is frequent on Microsoft Exchange servers. For some obscure reason, they default the HELO with their local name (ex: mail.company.local). This local name is invalid and unreachable on the internet.

If your server HELO command is not FQDN compliant, the SPS server will terminage the connection with an error message:

  • Helo command rejected: Host not found.
  • Helo command rejected: Invalid name.
  • Helo command rejected: need fully-qualified hostname.

Frequently asked questions

How come I can send emails to company A but SPS rejects my emails?

The SPS server is enforcing 15+ years old rules in order to decrease the spam volume. Our server is just less tolerant to misconfigured email servers.

Can you add our company to your whitelist?

There is no whitelist at this level. Your server is either compliant and the email gets thru. Or it is not compliant and the email is rejected. The concept of whitelist only happens at the anti-spam level.

Did SPS change its email server configuration recently?

The incoming email filter parameters have not changed since april 2008.