SMTP Connection timeout when trying to connect to Messagelabs Clusters

Products

• Email Security.cloud

Issue/Introduction

Clients may report a connection timeout error when trying to connect to our clusters , example for inbound :   cluster5.eu.messagelabs.com or for outbound :   cluster5OUT.eu.messagelabs.com

 

Environment

Release : 10.8.0

Cause

The timeout issue is due to a connection refused at the client side due to a Proxy / Firewall deferring the connection.

 

Resolution

Clients can perform a connection Telnet test to their cluster on port 25 in order to confirm. 

If the matter impacts inbound , then the test would be Telnet cluster5.eu.messagelabs.com 25

If outbound is impacted , the test would be Telnet  cluster5OUT.eu.messagelabs.com 25

A successful result should display :   

Connection Status : Connection to cluster5.eu.messagelabs.com on port 25 was successfull

220 server-14.tower-728.messagelabs.com ESMTP