What's new for transport rules in Exchange Online
Applies to: Exchange Online
Topic Last Modified: 2013-07-03
This topic provides a brief overview of some of the key changes and enhancements in Exchange Online for Transport rules.
Data loss prevention (DLP) features in Exchange Online can help organizations reduce unintentional disclosure of sensitive data. Transport rules have been updated to support creating rules that accompany and enforce DLP policies. To learn more about DLP support in transport rules, see the following topics:
The functionality of transport rules has been extended via the addition of new predicates and actions. Each predicate listed below can be used as a condition or an exception when you're creating transport rules.
For detailed information about using these new predicates and actions, see New-TransportRule.
Support for extended regular expression syntax Transport rules in Exchange Online are now based on the Microsoft .NET Framework regular expression (regex) functionality and now support extended regular expression syntax.
Detailed Transport rule information in message tracking logs Detailed information about Transport rules are now included in message tracking logs. The information includes which rules were triggered for a specific message and the actions taken as a result of processing those rules.
New rule monitoring functionality Exchange Online monitors Transport rules that are configured and measures the cost of running these rules both when you're creating the rule and also during regular operation. Exchange can detect and generate alerts for rules that are causing delays in mail delivery.
Rule size limit changes The following changes have been made to Transport rule limits:
Maximum size of each rule is 4 kilobytes (KB).
The character limit for all regular expressions used in all Transport rules is 20 KB. This limit applies to total number of characters used by all regular expressions, including keywords.