Your login for our support center is different than your Control Panel login.

Click here to create a login for the support center

 Knowledgebase
Knowledgebase
SocketLabs On-Demand Inbound SMTP Restrictions

Inbound SMTP Restrictions

In order to provide the highest level of service our inbound injection network has the restrictions listed below when injecting inbound messages for relay.

-Maximum of 20 simultaneous connections per IP may be established to smtp.socketlabs.com

-Maximum message size, including any embedded images and attachments, is 40MB

-Maximum 500 total recipients per message

More Information

See our other KB articles for more information on related topics.

IP Addresses, Ports, and more inbound SMTP connection information:  http://support.socketlabs.com/kb/94/

To better troubleshoot and diagnose SMTP connectivity issues see our blog on Diagnosing SMTP Service Connection Issues

Related Errors

If your message is larger than 40MB you will receive the following error: 552 5.3.4 - Message too big for system

For more information about this error please see http://support.socketlabs.com/kb/87/

 

If you attempt to send to more than 500 addresses in one message you will receive the following error: 452 5.5.3 - Too many recipients

For more information about this error please see http://support.socketlabs.com/kb/85/

 

If you attempt more than 20 connections you will receive the following error: 421 4.4.5 - Too many connections from your host

For more information about this error please see http://support.socketlabs.com/kb/86/

 


Comments (0)
Help Desk Software by Kayako  Copyright © 2018 SocketLabs, Inc.  Terms of Service | Privacy Policy | Acceptable Use Policy