SMTP server configuration

This article describes checks, that are performed on the shared smtp server smtp.forpsi.com, and errors, that can be displayed when sending emails via this smtp server. Checks are important because of preventing of overloading and spamming thrue this smtp server. Primarily to ensure delivering legit emails, that are sent via this smtp server.
 

Connection to the SMTP server is available on ports 25, 587 and 465. We recommend TLS secured connection on port 587 or SSL secured connection on port 465. TLSv1.2 and 1.3 are supported. Authoriazation (PLAIN or LOGIN) is required.

Note: Internet service providers often disable communication on the port 25 to prevent spamming from PCs with virus. To prevent trouble with the disabled port 25, we recommend to use the port 587 or the port 465 along with an encrypted connection (SSL) for the SMTP server.

You can find setup guides for individual email clients in the sections

Email clients - IMAP
Email clients - POP3 
Outlook 365 (2016 and newer) 

SMTP server is realized by solution Cloudmark Gateway provided by Cloudmark, Inc. Cloudmark Gateway is one of the most accurate and scalable carrier-grade solution, which provides effective protection against overloading of the server or messaging abuse such as spam, phishing, and viruses.
 

• Authentication

The SMTP server requires authentication. The SMTP server supports the LOGIN and PLAIN methods of authorization. You need to enter correct username (email address) and password. If you don't set using authentication for your email account, you need to edit configuration of email account in your email client, see articles in the section Email clients (in Czech).
Error:

5.1.0 piWs1j0010jifNx01iWsdh authentication failed

• Sender's domain must be the same as domain used for authentication or this domain's alias

Error:

5.1.0 <john.smith@domain.com> sender rejected

• Valid MX or A DNS record 

For more information see the article SMTP server configuration - DNS records check.
 

• GeoIP  protection

It is allowed to send emails only from given countries in default setting, see the article GeoIP - allowed countries. If you need to send your emails from other country, send to us the authorized ticket with your domain and the country, you want to allow.
Error:

5.1.0 <john.smith@domain.com> sender rejected GeoIP

Note: It can happen that if you travel abroad, you won´t be able to send your emails, although sending emails from the country is enabled. This can happen because the local Internet service provider blocks communication on the port 25. In such case, we recommend to use the port 587 or the port 465 along with an encrypted connection (SSL) for the SMTP server.

Note: From webmail you can send emails from any country.
 

• Limits

Limits of sending emails per unit of time:

250 messages per 1 minute
1000 messages per 1 hour
20000 messages  per day

Error:

5.1.0 piWs1j0010jifNx01iWsdh policy violation

Limit of recipients of one message: 250
Error:

5.1.0 piWs1j0010jifNx01iWsdh too many recipients

Limits of messages in one session: 250Error:

5.1.0 piWs1j0010jifNx01iWsdh too many big messages to Seznam.cz

When you send bigger amounts of emails from one email or IP, no more than one half of the messages can be left in the mailserver's queue.
Error:

5.1.0 piWs1j0010jifNx01iWsdh policy violation

For more information see the article SMTP server configuration - limits.
 

• Except of the first few messages, all messages certified as spam will be rejected

When messages sent during one day from one IP or one sender are certified as spam, only first few of them will be accepted by the antispam system and delivered to the recipients. All other messages sent from the same sender (IP) will be rejected with this error:

5.1.0 piWs1j0010jifNx01iWsdh spam detected

What to do if you get this error message: contact us on portal  support.forpsi.com, send us a new ticket with the source code of your message and the text of the error message.

Note: Emails containing a virus are rejected. Emails with attachment with denied extension (com, exe, pif, bat, scr, cpl, cmd, dll, lnk, inf, msi, sct, vbs, vb, vbe, js, wsf, iso, hta) are rejected too.

Sending spam messages through our SMTP server can lead to placing it on various blacklists. For this reason, it is very important to prevent sending spam messages - for example from abused email accounts. In rare cases, a correct email might be marked as a spam, for this reason, we have configured our system so that it accepts few first emails.

• Emails containing virus or bad attachment are rejected

 Emails containing virus are rejected. Emails containing attachment with denied extension (com, exe, pif, bat, scr, cpl, cmd, dll, lnk, inf, msi, sct, vbs, vb, vbe, js, wsf, iso) are also rejected. You can get these errors:

5.1.0 piWs1j0010jifNx01iWsdh virus detected

5.1.0 piWs1j0010jifNx01iWsdh Bad attahment

What to do if you get this error message: If you have attached a file with denied extension, pack this file for example as zip and send it again.
 

• TLS support

 Now, it is possible to use the secured TLS connection not only for the SMPT connection email client > the smtp server smtp.forpsi.com, but also for the connection smtp.forpsi.com > recipient's server. If you want to use this possibility, contact us on support.forpsi.com.
 

• The SPF record