To successfully deliver email to a client hosted by Inteq, your email server needs to adhere to some basic rules.
1. a valid Reverse DNS (rDNS) record for the connecting IP. This should be setup by your hosting company, ISP or your technical department if you own a subnet.
2. a valid HELO name for the connecting IP. This must be setup on your mail server by your technical department and must be a valid and fully qualified domain name (ex: mail.domain.com).
3. the SMTP HELO banner must contain the fully qualified domain name (mail.domain.com).
4. your IP must not be listed in any major Real Time Blocklists/Blacklists (RBL).
5. your email server software and clients (MTA/MUA) must adhere to RFC standards.
6. do not attach dangerous/executables files to your outgoing messages.
7. setup DKIM, SPF, DMARC at minimum on your MTA and make sure you are sending mail only from delegated IPs.
8. check your mail server setup at http://mxtoolbox.com and fix any problem before opening a ticket with Inteq.
Please also read RFC 1912
Email REJECT codes:
RC554-1
This is a permanet REJECT error.
Probable reason: We have seen a large volume of SPAM originating from your mail servers.
Please check your hosts for bots/viruses and try again after the problem is fixed.
RC554-2
This is a permanet REJECT error.
Probable reason: Your MTA is not RFC compliant.
Please check your MTA setup and try again after the problem is fixed.
RC554-3
This is a permanet REJECT error.
Probable reason: Your email server is listed in a public RBL.
Please delist your domain and/or IPs/Subnets and try again after the problem has been fixed.
RC554-4
This is a permanet REJECT error.
Probable reason: Marketing or commercial emails sent to accounts without subscribing first.
No delisting.
RC554-5
This is a permanet REJECT error.
Probable reason: Your hosting or ISP provider has been blocked permanently.
Massive SPAM or malware originating from multiple hosts on the same subnet.
Most likely a bot network or a very compromised subnet.
RC554-6
This is a permanet REJECT error.
Probable reason: We are experiencing massive SPAM traffic from your country.
For the moment, connections from your country are REJECTED.
We understand that this is an extreme measure and might cause legitimate email to be REJECTED.
RC554-rDNS
This is a permanent REJECT error.
Your server should not retry delivery automatically.
Probable reason: Your email server does not have any kind of rDNS (Reverse DNS) or your rDNS is incorrect.
Our servers require a valid rDNS for any connecting MTA.
Ask your ISP or hosting provider to setup a rDNS for your connecting IP and then try again.
554 5.7.1 Client host rejected: cannot find your hostname, [Your.Server.IP]
This is a permanent REJECT error.
Probable reason: Your connecting IP does not have a valid HELO/rDNS or there is no A record in your DNS with the supplied HELO/rDNS.
Please fix your HELO/rDNS setup and try again.
450 4.7.1 Recipient address rejected: Delivery from your host is temporarily unavailable, please try later
This is temporary REJECT error.
Probable reason: Your IP is greylisted.
Your MTA should automatically retry delivery after some time.
Please open a support ticket to have your domain whitelisted.
504 5.5.2 <COMPUTERNAME>: Helo command rejected: need fully-qualified hostname
This is a permenant REJECT error.
Probable reason: Your MTA HELO is not a fully qualified host name.
Fix your MTA setup and try again.
If you are the owner of a domain and/or IP/Subnet and you have delivery problems to one of our client's domains, please open a support ticket at helpdesk [at] inteq [dot] ro with complete details.
Please note that:
- we whitelist inbound at our client's request or at the request of the sender ONLY IF we detect a false positive in our detection system.
- a single failure in providing fast and permanent unsubscribe from your newsletters/lists, will result in permanent REJECTION, without the possibillity to delist.
- receiving emails for several "unknown recipients" will result in a temporary REJECT which will become permanent if the situation continues. Please check you lists/recipients.
- including any "legal" text about your right to SPAM our clients will not help your delivery.
- all maketeers are required to use double-opt-in for their newsletters.
- repeated offenders will be REJECTED permanently.
Our system might report false positives from time to time.
If such is the case, please do report any problems to helpdesk [at] inteq [dot] ro
We go to great lengths to ensure a secure and professional email service to our clients as well as preventing outgoing threats and SPAM originating from our network.
Please respect our work, our clients and the law.
