Preserving Sender Reputation - Port25 Solutions, Inc.

Here are a few rules you can implement when “back-off” mode istriggered:• Send an email alert to one or more addresses• Dynamically change the retry schedule for that queue• Dynamically apply per-queue delivery throttling• Dynamically reroute messages from one VirtualMTA toanother VirtualMTA• Automatically use a different IP to send the message• Limit the amount of messages sent per hour, minute, or second• Resume Normal Delivery speeds after a successful delivery of an email• Reduce the amount of open connections to an ISPThe dynamic reroute feature combined with the ability to have separateper domain configurations per VirtualMTA, allows one to use the fullrange of domain directives beyond the new back-off directives, as wellas VirtualMTA attributes, for the fallback queue. A chain of backoffVirtualMTAs is also supported within SMTP response matching, that isperformed based on a list of perl-compatible regular expressions, enteredin a smtp-pattern-list directive in the configuration file.For example, you could define a list of errors that might occur duringdeliveries to Hotmail, in a smtp-pattern-list named Hotmail-errors, andspecify that the queue be put in backoff mode in case of a match: Here isa list of potential scenarios that would trigger automatic back off mode fora given ISP, in this case Hotmail:• generating high volumes of complaints from Hotmail/ mode=backoff• Excessive unknown recipients - possible Open Relay/ mode=backoff• Too many 421 errors/ mode=backoff• Blocked by spamhaus/ mode=backoff• 451 Rejected/ mode=backoffThis document contains confidential and proprietaryinformation belonging to Port25 Solutions, Inc. Theinformation in this document may not be disclosed toothers, copied or reproduced in any way without the priorpermission from Port25 Solutions, Inc. Copyright © 2013All rights reserved.5