Dear valued client,

Please be informed that for shared hosting servers, we are using our configured outgoing smarthost SMTP IP that belongs to the our IP range.

For Dedicated Server/VPS, our clients are using dedicated IPs that belong to our own IP pools.

There are all kinds of Spam database out there to protect their own structure and we actively monitor DNSBLs that could impact delivery across the entire environment.

What is DNSBL?

Domain Name System Blacklist (DNSBL) or Real-time Blackhole List (RBL) is a service whereby with a simple DNS query mail servers, you can check whether a sending IP address is on a blacklist of IP addresses reputed to send email spam. 

If our IP addresses appear on a list, we will take immediate action to have that address removed from the DNSBL as soon as possible.

However, we do not monitor UCEPROTECT because of their specific listing and delisting practices.

Here are some sample messages:

A) Remote Server returned '554 5.7.1 <domain that rejected the email> #5.7.1 smtp; 554 5.7.1 Service unavailable; Client host ] blocked using

B) Remote Server returned '554 5.0.0 <domain that rejected the email> #5.0.0 smtp; 550-XXX Anti Spam Engine has blocked this Email because the sender IP 550 Address is blocklisted.>

C) '<email@address>: host <host that reject the email> error: said: 553 NET xxxx is UCEPROTECT- listed

We take necessary measures to prevent our IPs from being identified as a spam source.

At the same time, we advise our customers and their email recipients to avoid using UCEPROTECT Level-3 that is too aggressive.

Last but not least, please do not hesitate to contact our professional technical team with a full bounce back email header for assistance if you receive a return mail with a similar message.

Thank you very much for your attention!

Have a nice day.

Support Team


Technical Support Department