MailRoutingHosts LDAP Attribute



 Syntax 

 directory string (UTF-8) 

 OID 

 2.16.840.1.113894.1009.1.101.0.1102.1.1 



Definition

Fully qualified host name(s) of the MTA(s) responsible for making routing decisions for users in this (and all contained) domain(s). The absence of this attribute implies all MTA&#x27;s must route messages for the users/groups of this (and contained) domain(s).

When a domain is found to be non-local, the use of this attribute depends on the value of the  MTA option:



 If the value is zero (0), which is the default setting, the    attribute was checked as part of the $&#x2a; rewrite rule. With a    non-local domain, the $&#x2a; rewrite rule fails and no further use is     made of this attribute&#x27;s values. The remaining rewrite rules    determine the handling of the domain. 

 If the value of the option is one (1), then the first value of    this attribute that the MTA receives is installed as the source     route in the address. And, all addresses associated with the    domain are routed to that host. 



Since this attribute is multi-valued and the first value the MTA "sees" will be chosen when the option is set to 1, it might be tempting to assume that you can direct the order in which these mail hosts will be used; that is, you might assume you can do a sort of load balancing by ordering the various values of this attribute. But, LDAP does not guarantee that attribute value ordering is preserved, so the first value seen by the MTA might be any of the attribute&#x27;s values, not necessarily the first one in the LDAP entry.

You can implement load balancing with a set of MX records for each of the routing host names. Do not attempt to do it with the ordering of this attribute&#x27;s values.

The  MTA option may be used to specify a different attribute name for this function.

Example mailRoutingHosts: mail.siroe.com