T-Online: 554 - Dialup/transient IP not allowed
In addition to the regular requirements for sending e-mails to Telekom servers, additional measures are required for incoming e-mails to be accepted.
Please note that the rules listed in this article have been defined exclusively by T-Online and that we have no influence on the process for incoming e-mails to @t-online.de addresses.
Error message
554: Dialup/transient IP not allowed.
Use a mailgateway or contact toda@rx.t-online.de if obsolete. (DIAL)Description
T-Online describes the technical requirements for sending e-mails on https://postmaster.t-online.de/. Section 4.1](https://postmaster.t-online.de/#t4.1) describes the requirements for smooth access to the T-Online Mail Exchange. The error message Dialup/transient IP not allowed is returned by Telekom, among other things, if no valid imprint can be determined for sending e-mails.
Solutions
Provide an imprint with contact options for the technical full-qualified domain name (FQDN) or use our SMTP e-mail gateway.
Solution 1: Store imprint
To fulfill the information obligation, you can configure an imprint for the technical host name of your server. If you use the Plesk Control Panel on your creoline server, log in to the Plesk Control Panel and create a new website for the technical host name. Example: s12345.creolineserver.com. Enter the imprint of your company with the corresponding contact options here. If no Plesk Control Panel is in use, create a new virtual host for the technical host name of your server and store the corresponding legal notice there.
Please also note Article 5 of Directive 2000/31/EC:
https://eur-lex.europa.eu/legal-content/DE/TXT/HTML/?uri=CELEX:32000L0031
Then inform Telekom via toda@rx.t-online.de about the stored imprint so that the block can be removed.
The e-mail must contain the following information:
- IP address of the server
- Host name of the server
- Link to the imprint
Solution 2: Send connector
An unmanaged server is required for this solution variant, as changes must be made using root rights.
In addition to sending emails directly from your creoline server, you can also set up our send connectors for outgoing emails. In this case, outgoing e-mails are not routed immediately to the determined mail exchange server (MX), but are sent via our decentralized e-mail cluster.
To set up a send connector, you must first set up a send connector via our customer center. To do this, navigate to account.creoline.com → E-Mail Protection → Send Connectors. The ownership must then be verified for each sending domain using a DNS TXT entry. As soon as the ownership has been verified, you can store the send connector in the Postfix configuration.
Related help center articles:
Solution 3: Customize technical hostname
An unmanaged server is required for this solution variant, as changes must be made using root rights.
In addition to the solutions presented, you can also customize the hostname of your server to send emails via a technical hostname managed by you. Please note that you must also customize the RDNS name of your server to comply with the RDNS policy.
Change the technical host name as well as the RDNS entry of your server e.g. from sXXXXX.creolineserver.com to mail.your-domain.de. Then make sure that your company's legal notice is displayed correctly when mail.your-domain.de is called up.
Related help center articles:
Then inform Telekom via toda@rx.t-online.de about the adjusted host name so that the block can be removed.
The e-mail must contain the following information:
- IP address of the server
- Hostname of the server